CHAPTER III

Scenario Descriptions Introduction Figure III-1. Illustrative Size and Weight Scenarios

The outreach process Base Case versus Uniformity described in Chapter I identified a number of truck size and weight (TS&W) H.R. 551 issues of broad interest. Those issues were North American Trade incorporated into a set of illustrative scenarios that Longer Combination reflected changes in various Vehicles Nationwide Federal TS&W regulations. Potential impacts of those Triples scenarios were analyzed Nationwide against base case impacts of maintaining current Federal TS&W regulations. Figure disposition toward a III-1 shows the five particular TS&W policy illustrative scenarios option. Rather, they were analyzed in this study: selected to illustrate potential The Base Case provides a • Uniformity impacts across a broad range point of reference for the • North American Trade of possible TS&W changes. scenario analyses. It • LCVs Nationwide represents the motor carrier • H.R. 551 This chapter describes the and rail industries in the year • Triples Nationwide illustrative scenarios in 2000, absent any significant detail. The scenarios changes in Federal or State The H.R. 551 and Triples address a wide range of TS&W limits. Nationwide scenarios are issues, and were specified to subsets of the Uniformity estimate the upper range of Introduction Scenario and the LCVs impacts that might be Nationwide Scenario expected from various types The Base Case retains all respectively. They are of TS&W policy changes. features of current law. indented in Figure III-1 to Under different assumptions Federal size limits [102-inch show this relationship. about the vehicle weights and maximum vehicle width, dimensions that might be 48-foot minimum semitrailer In addition, a Base Case was allowed under each scenario length limits or longer if established against which the or the networks of highways grandfathered (see Figure III- illustrative scenarios are that might be available for 2), and 28-foot minimum compared. certain vehicles, the trailer length limits for estimated impacts might be double-trailer combinations] These scenarios should not lower. remain on the Interstate be construed as being System and other highways indicative of the Department of Transportation’s (DOT’s) Base Case on the NN. Operation of commercial motor vehicle Figure III-2. State Semitrailer Lengths on the NN combinations with two or more cargo-carrying units on The Surface Transportation Assistance Act of 1982 the NN are restricted to mandated minimum semitrailer lengths of 48 feet. length limits in effect on June However, in those States having semitrailer lengths longer 1, 1991. than 48 feet, these lengths became the (grandfathered) minimum. The current Federal weight limits on Interstate highways Alabama 53'6" Montana 53'0" and bridges [20,000-pound Alaska 48'0" Nebraska 53'0" single-, 34,000-pound Arizona 57'6" Nevada 53'0" tandem-axle, 80,000-pound Arkansas 53'6" New Hampshire 48'0" gross (GVW) cap, and Federal Bridge California 48'0" * New Jersey 48'0" Formula (FBF)] continue, as Colorado 57'4" * New Mexico 57'6" do existing grandfather rights. Connecticut 48'0" New York 48'0" Operation of LCVs on the Delaware 53'0" North Carolina 48'0"

Interstate Highway System, is District of Columbia 48'0" North Dakota 53'0" restricted by State law in Florida 48'0" Ohio 53'0" effect as of June 1, 1991. Georgia 48'0" Oklahoma 59'6" The analysis year for the Hawaii 48'0" Oregon 53'0" study is 2000. Projections of Idaho 48'0" Pennsylvania 53'0" the truck fleet and truck VMT Illinois 53'0" Puerto Rico 48'0" are based on trends from Indiana 48'6" * Rhode Island 48'6" 1994, the base year for both Iowa 53'0" South Carolina 48'0" this study and the 1997 Kansas 57'6" South Dakota 53'0" Federal Highway Cost Allocation (HCA) Study. Kentucky 53'0" Tennessee 50'0" Based on a review of many Louisiana 59'6" Texas 59'0" studies, the fleet and VMT Maine 48'0" Utah 48'0" were projected to increase at Maryland 48'0" Vermont 48'0" an annual rate of 2.6 percent Massachusetts 48'0" Virginia 48'0" a year between 1994 and Michigan 48'0" Washington 48'0" 2000. Minnesota 48'0"" West Virginia 48'0"

Mississippi 53'0" Wisconsin 48'0"

Missouri 53'0" Wyoming 57'4" * King pin regulation applies Source: 23CFR 658, Appendix B

III-2 Table 1. Base Year and Forecast Commercial Vehicle Fleet and Travel

Number of Vehicles Vehicle Miles Traveled (in millions) Vehicle Class Percent Percent 1994 2000 Share of 1994 2000 Share of Truck Fleet Truck Fleet

3-axle single unit truck 594,197 693,130 24.9 8,322 9,707 7.6

4-axle or more single unit truck 106,162 123,838 4.4 2,480 2,893 2.2

3-axle tractor-semitrailer 101,217 118,069 4.2 2,733 3,188 2.5

4-axle tractor-semitrailer 227,306 265,152 9.5 9,311 10,861 8.5

5-axle tractor-semitrailer 1,027,760 1,198,880 43.0 71,920 83,895 65.4

6-axle tractor-semitrailer 95,740 111,681 4.0 5,186 6,049 4.7

7-axle tractor-semitrailer 8,972 10,466 0.3 468 546 0.4

3- or 4- axle truck-trailer 87,384 101,934 3.6 1,098 1,280 1.0

5-axle truck-trailer 51,933 60,579 2.2 1,590 1,855 1.4

6-axle or more truck-trailer 11,635 13,572 0.5 432 503 0.4

5-axle double 51,710 60,319 2.2 4,512 5,263 4.1

6-axle double 7,609 8,876 0.3 627 731 0.6

7-axle double 7,887 9,201 0.3 542 632 0.5

8-axle or more double 9,319 10,871 0.4 650 759 0.6

Triples 1,203 1,404 0.0 108 126 0.1

Characteristics of the Base and Reebie Associates. This those likely to be Case commercial vehicle report projects an annual impacted by changes in fleet are consistent with those growth rate for rail car miles TS&W limits were explicitly in the HCA Study. The HCA of 2.2 percent to the year considered in the study. Study provides VMT for 2000. Rail intermodal car Table III-2 shows selected vehicle classes miles were projected to grow characteristics of how those disaggregated by weight at 5.5 percent per year. vehicles are currently used. group, highway functional class, and State. Scenario Specifications The impact that base year (1994) truck operations The rail base case was The number of trucks would have on infrastructure projected to the year 2000 estimated to be in the truck costs (bridge, pavement, using the “International and fleet and the extent of their roadway geometry), safety, Domestic Freight Trends” use in 1994 and 2000 are traffic operations, energy and report by DRI/McGraw-Hill shown in Table III-1 Only environment, shipper costs,

III-3 and rail industry marine links for connection to competitiveness was the major U.S. truck and rail A myriad of TS&W compared to the impact that networks. regulations affects U.S. truck operations would have trucking operations. These in 2000 if no significant The Networks differences reflect variations TS&W policy changes in economic and industrial occurred. This comparison Single unit trucks (SUTs) and activities, freight flow shows how changes shorter single-trailer truck characteristics, infrastructure estimated to occur between combinations have access to design and maintenance 1994 and 2000, essentially virtually all highways. philosophies, system due to growth in travel “STAA” double trailer condition, traffic densities demand, would compare to combinations and and modal options. impacts expected to result combinations with 48-foot Many believe that grandfather from TS&W policy changes semitrailers operate on a rights create enforcement in the year 2000 Base Case. 200,000-mile network problems. Also, there is designated under the Surface concern that vehicles with The Vehicles Transportation Assistance potentially damaging axle Act of 1982 (STAA). weights may be allowed to The truck configurations Combinations with semi- operate under grandfather analyzed in this study and trailers longer than 48 feet provisions. Equity issues are their current use in terms of generally must comply with also important in that carriers areas of operation, length of State routing requirements in one State are afforded haul, types of commodities and provisions to minimize valuable operating privileges carried, and highways used vehicle offtracking. that are denied to shippers are described in Table III-2. and carriers (and the The maximum weights and Access Provisions industries they represent) in dimensions allowed for these neighboring States. Finally, configurations in each State STAA combinations safety and congestion issues have been modeled by (vehicles authorized under related to large trucks are of dividing the country into six the STAA legislation) are increasing concern to auto, as regions (see Figure III-3) and given access to terminals well as truck drivers. This selecting the median weights (points of loading and scenario is designed to test and dimensions for the unloading) and service the impact of removing the configurations from among facilities (for food, fuel, rest, grandfather provisions and the States in the region (see and repair) under State Tables II-2 to II-4 in Volume provisions that follow II). The regions are: North- Federal regulations called for east (14 States), Southeast (9 by the STAA. All States States), Midwest (9 States), must allow access for STAA South Central (2 States), vehicles from and to the NN West (14 States), and via any routes they can safely California. Alaska and negotiate. Hawaii have not been modeled as data were not available and they depend on Uniformity Scenario

III-4 applying Federal weight NN would have to lower NN would have to raise their limits to all highways on the those limits to the Federal limits. NN. States that currently limit, and the few States that have higher weight limits on have lower weight limits on non-Interstate portions of the non-Interstate portions of the

Table 2. Current Use of Scenario Vehicles Common Configuration Number Maximum Current Use Type of Weight (Pounds )

Single-Unit 3 50,000 Single-unit trucks (SUT) are the most commonly used Truck to trucks. They are used extensively in all urban areas for 65,000 short hauls. Three-axle SUTs are used to carry heavy loads of materials and goods in lieu of the far more common two-axle SUT.

4 or more 62,000 SUTs with four or more axles are used to carry the to heaviest of the construction and building materials in 70,000 urban areas. They are also used for waste removal.

Semitrailer 5 80,000 Most used combination vehicle. It is used extensively for to long and short hauls in all urban and rural areas to carry 99,000 and distribute all types of materials, commodities, and goods.

6 or more 80,000 Used to haul heavier materials, commodities, and goods to for hauls longer than those of the four-axle SUT. 100,000

STAA 5, 6 80,000 Most common multitrailer combination. Used for less- Double than-truckload (LTL) freight mostly on rural freeways between LTL freight terminals. B-Train 8 105,500 Some use in the northern plains States and the Northwest. Double to Mostly used in flatbed trailer operations and for liquid 137,800 bulk hauls.

Rocky 7 105,500 Used on turnpikes in Florida, the Northeast, and Midwest Mountain to and in the Northern Plains and Northwest in all types of Double 129,000 motor carrier operations, but most often it is used for bulk hauls.

Turnpike 9 105,500 Used on turnpikes in Florida, the Northeast, and Midwest Double to and on freeways in the Northern Plains and Northwest for 147,000 mostly truckload operations.

III-5 Figure III-3. Truck Size and Weight Analysis Regions

Historical Perspective created in 1991 and focuses System. Because some States on double-trailer or triple- already allowed motor Grandfather Provisions trailer combination vehicles carrier operations at higher operating at weights greater axle or gross weights, a Current TS&W law includes than 80,000 pounds. grandfather clause was three grandfather provisions included in the legislation to which allow higher State The Transportation Equity preclude a rollback in those TS&W limits than those Act for the 21st Century did States. indicated in the Federal not change existing regulations. The first, grandfather provisions. It did The Federal-Aid Highway adopted in 1956, is however, establish new Amendments of 1974 concerned with axle weights grandfather dates, by special (enacted in 1975) mandated and gross weights. exceptions to the rules, for that maximum weights for Maine and New Hampshire. axle groups would be The second, enacted in 1975, determined by a formula deals principally with bridge The Federal-Aid Highway designed to protect bridges. formulas and axle spacing Act of 1956 imposed axle A new grandfather provision tables. The most recent and GVW limits for trucks was included in the 1975 grandfather clause was operating on the Interstate legislation that allowed

III-6 States to continue to use provisions that created more alternative bridge formulas uniform TS&W standards This scenario examines the or axle spacing tables that nationwide. The act impact of establishing State allowed weights greater than provided that Federal-aid truck weight limits at the the new Federal formula. funds would be withheld current Federal limits for all The grandfather provisions in from States that enacted trucks operating on the NN. the 1956 and 1975 maximum weight limits lower All State grandfather rights legislations have been than the maximums specified would be eliminated. Non- interpreted to include by Federal law. These limits divisible load permits would exemptions for both are 20,000 pounds for single continue. Off the NN, permitted and non-permitted axles, 34,000 pounds for vehicles would continue to vehicles. Figure III-4 tandem axles, and GVWs operate at current State- explains divisible and non- determined by the FBF, regulated weights. divisible permitting subject to an 80,000-pound regulations and practices. maximum limit. The Vehicles

The Intermodal Surface It raised the maximum Under the Uniformity Transportation Efficiency Act vehicle width limit from 96 Scenario, single unit trucks (ISTEA) of 1991 froze the inches to 102 inches, and, as (SUTs) were analyzed as weight, length, and routes of amended, applied this limit to follows: (1) the maximum LCVs operating on the the NN, subsequently GVW for three-axle trucks Interstate System as well as designated by the Federal would be 51,000 pounds and the lengths and routes of Highway Administration and (2) the maximum GVW for commercial vehicle States, as required by the four-axle trucks would be combinations with two or STAA of 1982. reduced to 56,500 pounds. more cargo carrying units These weights assume short operating on the NN. With It also set minimum length wheelbase vehicles, with this legislation, operations of limits of 48 feet (or longer if weights determined by FBF. LCVs, defined as any grandfathered) for semi- This assumption may combination of a truck tractor trailers in a single-trailer overstate the impact of this and two or more trailers or combination and 28 feet for scenario because longer semitrailers which operate on trailers in a double-trailer wheelbase vehicles could the Interstate System at a combination. It required the continue to operate at higher GVW greater than 80,000 States to allow trailers these weights. Also, pounds, are restricted to the lengths or longer on their NN manufacturers would types of vehicles and routes routes. However, the States probably build longer in use on or before June 1, are permitted to allow longer wheelbase vehicles to 1991. trailers. The STAA also required the States to provide reasonable access for these Uniformity Legislation STAA vehicles between the NN and terminals and service The STAA of 1982 included facilities.

Scenario Specifications

III-7 Figure III-4. Divisible and Non-divisible Load Permits

States grant special permits exempting eligible motor carrier operations from Federal gross vehicle weight (GVW), axle weight and bridge formula limits. Federal law authorizes all States to issue permits for non-divisible loads, and 21 States allow the operation of overweight divisible loads under grandfathered special permits. The interpretation of divisible versus non-divisible loads, however, varies from State to State.

In 1994, the Federal Highway Administration defined a non-divisible load or vehicle as one that exceeds “applicable length or weight limits which, if separated into smaller loads or vehicles, would (1) compromise the intended use of the vehicle . . . , (2) destroy the value of the load or vehicle . . . , or (3) require more than eight work hours to dismantle using appropriate equipment. . . .” (Part 658 of Title 23, Code of Federal Regulations).

However, because the definition is not commodity-specific and because States are left to interpret the definition in application, there is ambiguity about what loads qualify as non- divisible and, therefore, may be treated specially. For example, some States consider equipment that has been spot-welded to be divisible, while other States categorize such equipment as non-divisible. Further the burden of proof as to the effort required for dismantling lies with the applicant, and there is substantial variation between States as to the amount of proof required to demonstrate that dismantling a load requires more than eight hours of work.

The weights that can be allowed under non-divisible load permits are not restricted by Federal regulation. These permits are usually issued for a specific route, often for an individual trip. They may be issued for very high GVWs, but the number of axles required generally goes up with GVW. Examples of non-divisible loads include manufactured homes, boats, cranes, mining equipment, major pieces of machinery, construction equipment, and power plant components.

In contrast to non-divisible loads, divisible load permits apply to all other material. They are generally issued for regular operations at a specified GVW, usually on a quarterly or annual basis. These permits apply to either entire systems or specified and often include restrictions concerning seasons and weather extremes. About half of the States have claimed grandfather clause authority to issue divisible load permits for operations over 80,000 pounds GVW on the Interstate.

Many States allow divisible load permits for specific commodities that are important to the economic health of their State. It is often argued, however, that exemptions are also instituted

III-8 operate at higher gross the NN. In those rare cases limited loads but not cube- weights. where weight limits are limited loads. For lower on the NN as example, a seven-axle All SUT unit and compared to Interstate triple-trailer combination combination vehicle types Federal limits, this currently operating under would be affected because scenario assumes that the grandfather provisions, at States would not have weights would be 115,000 pounds, would be grandfather rights to allow increased. However, it required to operate under operation of trucks with should be noted that the the 80,000-pound limit. GVWs or axle loads modeling capability greater than federally set underlying the study is not The Network limits. For example, a sufficiently sensitive to this seven-axle truck-trailer particular case. The analysis network combination, currently assumed for testing this allowed under grandfather The new limits would scenario was the NN. provisions in some States prohibit all LCVs from at a GVW of 105,500 operating above 80,000 Access Provisions pounds would be restricted pounds, rendering them to an 80,000-pound limit on impractical for weight Access provisions are

Figure III-5. Uniformity Scenario

Main Feature SU3 Ÿ Extend Federal gross Three-axle single unit vehicle weight limits on 51,000 pounds (maximum) States beyond the Interstate to National 3-S2 Network (eliminates grandfather provisions)

Five-axle semitrailer combination Available Highways 80,000 pounds (maximum) Ÿ National Network for Large 2-S1-2 Trucks

Five-axle STAA double-trailer combination Access Provisions 80,000 pounds (maximum) Ÿ Current Federal and State provisions

III-9 assumed unchanged from combination and the on the tandem axle of the the Base Case. eight-axle B-train second trailer. combination would have benefits in terms of trade, a A tridem-axle weight limit North American tridem-axle weight limit of of 51,000 pounds would Trade Scenarios 51,000 pounds would have assume 20,000 pounds on adverse bridge and safety the steering axle for an impacts, especially for the SUT, allowing up to 71,000 The North American Trade short wheelbase 4-axle pounds GVW. For a Scenarios are focused on SUT. The three scenario six-axle semitrailer trade among the North vehicles were also tested combination, 12,000 American trading partners. with tridem axle weight pounds is assumed for the Such trade could be limits of 44,000 pounds. steering axle and 34,000 facilitated by allowing the A 44,000-pound tridem pounds on the drive operation of six-axle axle weight limit could tandem, which would allow tractor-semitrailer provide a productivity up to 97,000 pounds GVW combinations at 97,000 increase for the scenario for this configuration. For pounds, which is sufficient vehicles while limiting an eight-axle B-train to carry a container loaded vehicle stability and combination operating at a to the International control as well as GVW of 131,000 pounds, Standard Organization infrastructure impacts. 12,000 pounds is assumed (ISO) limit on Interstate on the steering axle, 34,000 highways without a special A tridem-axle weight limit pounds on the drive axle, permit (as would be of 44,000 pounds would 51,000 pounds on the required under today’s assume 20,000 pounds on tridem axle of the first regulations). the steering axle for an trailer and 34,000 pounds SUT, allowing up to 64,000 on the tandem axle of the To provide for the pounds GVW. For a second trailer. operation of a six-axle six-axle semitrailer tractor semitrailer combination, 12,000 combination at 97,000 pounds is assumed for the pounds, a tridem weight steering axle and 34,000 limit of 51,000 pounds was pounds on the drive tested. Currently, the tandem, which would allow weight allowed on a up to 90,000 pounds GVW three-axle group is limited for this configuration. For Background: Policy by the FBF. Introduction of the eight-axle B-train Related Issues a tridem weight limit combination operating at a would potentially impact GVW of 124,000 pounds, North American the four-axle SUT as well 12,000-pounds is assumed Trade as the eight-axle B-train on the steering axle, 34,000 double combination. pounds on the drive axle, The United States, Canada, 44,000 pounds on the and Mexico signed the While the 97,000 pound tridem axle of the first North American Free Trade six-axle tractor semitrailer trailer and 34,000 pounds

III-10 Agreement (NAFTA) on and Mexico which pounds (assuming a December 17, 1992. establish tridem-axle 44,000-pound tridem-axle Among other objectives, weight limits by regulation, weight limit) or 97,000 NAFTA is intended to the U.S. does not legislate a pounds (assuming a promote competitiveness in tridem limit, rather it is 51,000-pound tridem-axle the global economy and to specified by the FBF. weight limit). This would provide for greater be accomplished by efficiency in transportation There are also significant allowing a higher tridem- among the North American differences in the single- axle weight limit and trading partners. By and tandem-axle weight raising the maximum GVW eliminating unnecessary limits among the United limit. barriers, the international States, Canada and Mexico. transport of goods and Table III-4 compares International services will be more single- and tandem-axle Container Traffic efficient. weight limits in the three countries. The United International containers are Figure III-6 compares the States and Canada have a significant and growing vehicle mix of the very similar weight limits feature of contemporary Canadian, American, and for single axles. Mexico, freight transportation. Over Mexican commercial however, is 10 percent the 10-year period between vehicle fleets. The six-axle higher for tandem-trailer 1987 and 1996, worldwide tractor semitrailer axles and 20 percent higher container port traffic grew configuration is widely for tandem drive axles than 124 percent. In the United used in both Canada and its NAFTA partners. In the States, container Mexico. This vehicle is case of tandem axles, there movements grew 62 practical in Canada and is an almost 9,000-pound percent during the same Mexico because they have difference between period of time (see Table tridem-axle weight limits Mexico’s limit of 42,990 III-5). for a 12-foot spread that pounds for a truck or truck- are considerably higher tractor tandem-axle and the An international container than the U.S. Federal limits U.S. Federal limit of enters the United States (see Table III-3). The 34,000 pounds. Canada through a marine port and is Canadian tridem-axle has an intermediate limit of usually transported to a rail weight limit ranges from 37,479 pounds. terminal or its final 46,297 pounds to 52,911 destination via truck. pounds, depending on how This scenario tests the These containers can cause far apart the axles are impact of allowing the six- a vehicle to exceed the spread. Mexico’s tridem- axle tractor semitrailer at Federal axle and/or vehicle axle weight limit is 49,604 weights of up to 90,000 weight limits. When pounds. Unlike Canada

III-11 Figure III-6. Comparative Fleet Profiles -- Canada, United States, and Mexico

Truck Configuration Canada United States Mexico

SU2 9.7% 35.5% 8.3%

SU3 2.3% 4.9% 15.3%

2-S1 1.6%

2-S2 5.5%

3-S2 51.0% 42.2% 35.2%

3-S3 18.5% 3.0% 37.3%

2-S1-2 2.7%

3-S2-2 5.2% 0.3%

3-S2-4 0.4% 2.5%

3-S2-S2 5.3%

3-S3-S2 7.9%

Other Configurations 0.1% 3.9% 1.4%

III-12 Table III-3. Tridem Axle Weight Limits at Various Axle Spacings

United States Axle Set Canada Mexico Federal State Max*

8 feet 46,297 34,000 44,000 49,604

8+ feet 46,297 42,000 58,400 49,604

10 feet 50,706 43,500 58,400 49,604

12 feet 52,911 45,000 59,400 49,604 * Grandfathered weights

Table III-4. Maximum Single and Tandem Axle Weight Limits – Canada, United States, Mexico

United States Axle Set Canada Mexico Federal State Max*

Steering Axle 12,125 - 13,000 14,330

Single Trailer Axle 20,062 20,000 22,500 22,046

Single Drive Axle 20,062 20,000 22,500 24,251

Tandem Trailer Axle 37,379 34,000 44,000 39,683

containers, particularly 40- III-6. Administration allows, at foot containers, are loaded State discretion, sealed to the weight limits A 20-foot marine container shipping containers moving established by the can be loaded to a gross in international commerce ISO—the principal weight of 44,800 pounds by to be carried at GVWs over international agency that ISO standards and may 80,000 pounds under non- sets standards for cause a bridge formula divisible load permits (see containers—they are violation in the United Figure III-7). However, generally too heavy for States. A 40-foot container this arrangement further trucks governed by U.S. can be loaded up to an ISO exacerbates the variability weight limits. Many of the weight of 67,200 pounds in U.S. weight limits. This NAFTA and European and may cause U.S. axle, creates difficulties for Community countries allow bridge and gross weight foreign shippers that may higher weights than the limits to be violated. not be United States. is demonstrated in Table The Federal Highway

III-13 impacts, particularly for Table III-5. Container Port Traffic bridges. As expected, the Year US Ports World tridem-axle weight limit of 44,000 pounds is 1987 14,048 65,844 relatively more 1988 15,252 73,810 infrastructure friendly than 1989 15,922 79,816 would be the 51,000-pound limit. 1990 16,651 85,957

1991 17,348 93,108 It should be noted that, in 1992 18,627 102,906 many States, these SUTs have grandfathered limits 1993 19,176 112,439 above the Federal limits. 1994 20,230 128,320 For example in Maryland

1995 21,347 135,000 and the District of Columbia, three-axle dump 1996 22,788 147,348 trucks with a special Source: Containerization International, Yearbook, 1984-1997. registration permit may

Thousands of Twenty-foot equivalent units operate at weights up to 65,000 pounds regardless of their wheelbase. In the Eastern coal producing familiar with the variance for four-axle SUTs. States, trucks for hauling in gross vehicle and axle Although the new limits coal generally are allowed load limits from State to provide for only somewhat to operate legally on State. higher payloads relative to designated highways or what can be carried today, with a permit at weights Four-Axle Straight these short wheelbase truck above the Federal limits. Trucks operations would be able to carry the weight on a much A tridem-axle weight limit shorter wheelbase without such as assumed in this excessive infrastructure scenario could also benefit short-wheelbase vehicles such as dump, refuse, ready Figure III-7. Non-divisible Load Permits for mix concrete, farm and International Containers construction vehicles. Evidence indicates that The Federal Highway Administration made a policy FBF is overly conservative decision in the early 1980's to allow goods transported in for short-wheelbase international containers to be treated as non-divisible vehicles. loads. Not all States utilize this provision. Some States require that U.S. Customs service container seals be broken Tridem-axle weight limits and a portion of the contents be removed when overweight of 44,000 pounds and containers are detected. 51,000 pounds are tested

III-14 Table 6. International Standards Organization Container Capacity

20-foot 40-foot Weight Containers Containers Configuration Container Plus Cargo Which may be Which may be (pounds) Legally Legally Transported Transported

United States Five-Axle Semitrailer 80,000 1 0 (without permit) Six-Axle Semitrailer 80,000 1 0

Canada Five-Axle Semitrailer 87,000 1 0

Six-Axle Semitrailer 102,500 1 1

Eight-Axle B-Train 137,800 1 1 Double

Mexico Five-Axle Semitrailer 97,000 1 1

Six-Axle Semitrailer 106,900 1 1

Nine-Axle Double 146,600 2 1

European Five-Axle Truck Trailer 88,200 1 0 Community Five-Axle Semitrailer 97,000 1 1

Six-Axle Semitrailer 97,000 1 1

Scenario Specifications axles were to be spread The eight-axle double more than this, pavement trailer combination is The Vehicles wear would increase while assumed to operate with bridge stress would two 33-foot trailers. This Figure III-8 summarizes decrease. Conversely, if vehicle, operating at assumptions in the North the nine feet were weights in excess of 80,000 American Trade Scenario. shortened, bridge stress pounds, would most likely The scenario tests the would increase, while operate with a “B-train” impact of introducing pavement wear would connection (see Chapter 8 tridem-axle weight limits decrease. on Safety Impacts). These of 44,000 pounds and vehicles are assumed to 51,000 pounds. These The four-axle SUT with a operate at weights of limits are applied to the 44,000-pound tridem-axle 124,000 pounds GVW with four-axle SUT, the eight- weight limit would be a 44,000-pound tridem- axle B-train double allowed to operate at a axle weight limit, and combination and the six- maximum GVW of 64,000 131,000 pounds GVW with axle semitrailer pounds and with a 51,000- a 51,000-pound tridem- combination. The tridem- pound tridem-axle weight axle weight limit. axle group has nine feet limit, at 71,000 pounds between the first and last GVW. axle in the group. If the

III-15 network in the same States. Figure III-8. North American Trade Scenarios For analysis purposes, the short-haul SUTs are not modeled using the study Main Features networks. In actual practice, these vehicles • Combination vehicles may travel anywhere, Four-axle single unit truck widely used in Canada without restrictions. A and Mexico 64,000 pounds or 71,000 more complete discussion • Introduces tridem-axle pounds maximum weight of the analytical approach weight limits is contained in Chapter IV. Available Highways Access Provisions • Current National The scenario assumes Six-axle tractor-semitrailer Network for STAA access provisions as in the 90,000 pounds or 97,000 vehicles Base Case, which implies pounds maximum weight Access Provisions access for eight-axle B- train combinations (with • Current Federal and 33-foot trailers) to and State provisions from the NN.

Eight-axle B-train double Longer Combination 124,000 pounds or 131,000 Vehicles Nationwide pounds maximum weight Scenario

The maximum GVW Turnpike Doubles (TPDs) The ISTEA of 1991, which allowed for a six-axle are assumed to operate on responded to public semitrailer would increase their current routes. concerns regarding the to 90,000 pounds or 97,000 However, for analytical safety of LCVs as well as pounds with tridem-axle purposes, the trips for concerns regarding rail weight limits of 4,000 RMDs and TPDs have been competitiveness, included pounds or 51,000 pounds, routed through that portion language to prevent the respectively. of the 42,500-mile long- expansion of LCVs into doubles network which is States that did not permit The Network available in the 14 them before June 1, 1991 westernmost States, (see Figure III-9). The analysis network for excluding Texas, New the six-axle tractor Mexico, California, Alaska The LCV Nationwide semitrailer and the eight- and Hawaii. For triples, axle B-train double is the the roadway network that is NN. Rocky Mountain modeled is the “LCV Doubles (RMDs) and region” of the 65,000-mile

III-16 Figure III-9. The ISTEA Longer Combination Vehicle Freeze

The Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 imposed a freeze on States to restrict the operation of Longer Combination Vehicles (LCVs) on the Interstate System to the type of vehicles in use on or before June 1, 1991. The ISTEA defined an LCV as a combination of a tractor and two or more trailing units weighing more than 80,000 pounds that operates on the Interstate. This freeze was continued with the Transportation Equity Act for the 21st Century.

In addition to freezing the weights, lengths and routes of LCVs on the Interstate System, ISTEA froze the lengths and routes of commercial motor vehicles (CMVs) having two or more cargo units on the National Network for Large Trucks. A CMV is a motor vehicle designed or regularly used for carrying freight, or merchandise, whether loaded or empty.

Because of the freeze, States that did not allow LCV operations prior to June 1, 1991 are precluded from allowing them or from lifting restrictions that governed LCV operations as of that date. Such restrictions may include route-, vehicle- and driver- specific requirements.

Scenario explores the The reader will note that a of the eastern turnpike impact of lifting the ISTEA tractor, twin 28-foot trailer States (e.g., those allowing freeze. New Federal limits combination weighing less LCV operations only on would be established and a than or equal to 80,000 turnpike facilities) have network of highways upon pounds is not considered an allowed LCVs for about 35 which these vehicles would LCV. This vehicle, the years. Some western be allowed to operate STAA double (sometimes States have permitted LCVs would be designated. referred to as a Western for fewer than 15 years. double), is allowed to Figure III-10 illustrates the operate in all States and in LCV operations are common LCV 1994 accounted for generally controlled combinations: the RMD, approximately 2.5 percent through special divisible the TPD, and the triple- of all truck combinations load permits. (See Figure trailer combination. A and 4.5 percent of all truck III-12). These permits diagram of the eight-axle combination VMT. typically, but not always, B-train double is also include limitations specific provided, although this Figure III-11 illustrates that to LCVs and may dictate vehicle, given current LCV usage is a regional equipment maintenance TS&W laws, is far less phenomenon. Of the 21 common than the other States that allow the LCVs. The figure also operation of LCVs, all but provides, for comparison, five are west of the typical non-LCV vehicles. Mississippi River. Some

III-17 Figure III-10. Comparison of Longer Combination Vehicles With Conventional Trucks Conventional Combination Vehicles

5-Axle Tractor Semi-Trailer 6Axle Tractor Semi-Trailer

STAA or “Western” Double

Longer Combination Vehicles (LCVs)

Rocky Mountain Double Turnpike Double

8-Axle B-Train Double Trailer Combination

Triple Trailer Combination

III-18 Figure III-11. States Allowing Various Longer Combination Vehicles States Allowing LCVs* States Allowing Triples

States Allowing Turnpike Doubles States Allowing Rocky Mountain Doubles

practices, driver in Florida and 131,060 operations and for liquid qualifications, and route pounds in Montana. bulk hauls. These selection, among other combinations are not factors. Background: Vehicle prevalent. Descriptions Most State LCV Rocky Mountain restrictions also include This section provides Doubles length and weight descriptions of the most provisions. In the majority prevalent LCVs operating The RMD consists of a of LCV States, maximum today. It should be noted, three-axle truck-tractor vehicle lengths for LCVs however, that eight-axle with a long front trailer are between 110 feet for B-train combinations at (40- to 53-foot) and a double-trailer weights over 80,000 shorter (20- to 28.5-foot) combinations and 115.5 pounds are allowed to rear trailer. A few toll feet for triple-trailer operate in the northern authorities in the east combinations; maximum plains States and the and weights range up to Northwest. They are used 147,000 pounds for TPDs mostly in flat bed trailer

III-19 Figure III-12. Special Permits for Longer Combination Vehicles

Most States that allow Longer Combination Vehicles (LCVs) require special permits for their operation. These permits generally certify that (1) drivers have adequate and specialized training and experience, (2) the equipment is sufficient for handling heavier loads, (3) the carrier is properly insured, and (4) the vehicle is properly maintained and meets safety standards. State permits may be issued for single trips or on an annual basis.

In addition to these permit provisions, many States have special equipment requirements for LCV operations. These may include splash and spray suppression devices (such as mud flaps) and axle requirements. Other restrictions could include operating requirements such as minimum speeds, designated lanes, mandated distances to complete passing maneuvers and, load sequencing of the combination’s trailers. Many States impose special driver requirements that are more extensive than those required for conventional trucks. These requirements may include minimum age limits and special training.

Special LCV permits often include route restrictions. Typically, these routes have, at a minimum, 12-foot lane widths, low to moderate grades, adequate space for executing turning maneuvers at intersections and curves, bridge load-bearing capacities necessary to tolerate heavier loads, suitable passing lanes, and a positive crash history.

midwest began to issue The TPD combination Compared to other LCVs, permits for RMDs in 1959. consists of a tractor towing TPDs have more cubic Western States followed in two long trailers of equal capacity and can carry the late 1960s. Today, length, typically from 40 higher weights. TPDs are RMDs operate over an feet to 53 feet in length. In particularly well suited to extensive network of the 1960s, several eastern operations where freight is highways and toll roads in States began permitting the moved from origin to 21 States (six turnpike use of these vehicles. destination without States and 14 western Today, 19 States allow intermediate pick-up or States). RMDs are such operations. The TPD delivery. generally used for general combination is allowed in freight and short resource all but three of the States in hauls. They are useful in which RMDs are allowed freight delivery to more to operate. These than one point on a route, operations are generally, because one trailer can be but not always, limited to dropped at an intermediate Interstate and toll road point. facilities. Turnpike Doubles

III-20 Figure III-13. Longer Combination Vehicles Nationwide Scenario

Main Feature 7-axle Rocky Mountain Double Maximum weight – 120,000 pounds • Broad national LCV operations

Available Highways

• RMDs and TPDs – 42,000 mile analysis network 9-axle Turnpike Double • Triples – 60,000 mile analysis Maximum Weight – 148,000 pounds network • 8-axle B-train double – National Network for STAA vehicles

Access Provisions 8-axle B-train Double Maximum weight – 124,000 pounds • RMDs and TPDs – none off the (33-foot trailers) analysis network • Triples – State issued permits • 8-axle B-train doubles – current Federal and State provisions

Triple-trailer combination Maximum weight – 132,000 pounds

Triples States on limited networks users of triples are the less- (on highways in 11 States than-truckload (LTL) A triple-trailer and on toll roads in three industry and major package combination generally States). They are usually express carriers. This consists of a two- or three- restricted to Interstate configuration allows the axle truck-tractor and three facilities and four-lane driver to drop off and pick trailers in tow. Each highways with low traffic up individual units at trailer is usually 28 feet to volumes. multiple points in a given 28.5 feet in length. Triple- run. In addition, LTL trailer combinations are In 1994, total VMT for loadings generally fill up usually restricted to triple-trailer combinations the trailer volume before maximum GVWs from was 108 million miles out they reach GVW limits. 105,000 pounds to 129,000 of 99,177 million miles Therefore, they benefit pounds. Triples are traveled by all combination from the additional cubic permitted to operate in 14 vehicles. The predominant capacity.

III-21 with two 33-foot trailers. Staging areas are assumed Scenario Description at key rural interchanges The Networks and the fringes of major The LCVs Nationwide urban areas. Work Scenario estimates the The analysis of this completed for this study impact of lifting the LCV scenario required use of all (see Chapter VII, Roadway freeze to allow LCV of the analytical networks Geometry) indicates that operations on a nationwide described in Chapter II. staging areas would be network. The LCVs would The 42,500-mile long- needed every 16 miles on be afforded higher GVW double network was used to rural freeways. On non- limits (see Figure III-13). simulate travel by the RMD freeway rural highways, All other Federal size and and TPD combinations. staging areas would be weight controls would The more extensive needed about every 50 remain. The scenario (65,000-mile) analytical miles. Urban staging area assumes that all States network was used to requirements are estimated would uniformly adopt the evaluate the operation of to range from 2 to 14, new limits, and therefore triple-trailer combinations. depending upon the number captures the maximum The eight-axle B-train of LCV routes approaching impact. double combination would a given area. Typically, be permitted to operate on the analysis indicates that The Vehicles the same network as STAA six staging areas are doubles which is the NN. required for each urban The longest and heaviest area. However, some configuration tested in this Access Provisions urban areas require scenario is the nine-axle significantly more, such as TPD. It would be allowed Because of poor offtracking Dallas which would need to operate at weights of up (cornering) performance, twelve. to 148,000 pounds GVW the analysis does not allow and have up to twin 53-foot long double-trailer Trucks with trip origins or trailers. The other LCVs combinations (TPDs and destinations in urban areas would also realize weight RMDs) off the designated would use urban fringe increases with the seven- analytical network. It is staging areas, while axle RMD being allowed assumed that drivers of through trucks would use to operate at 120,000 these vehicles will use the Interstate or other pounds, the eight-axle B- staging areas—large freeway system to their train double at 124,000 parking lots—to disconnect destination. The cost of pounds and the seven-axle the extra trailer and attach these facilities is set forth triple-trailer combination that trailer to another tractor in Chapter VII. at 132,000 pounds. RMDs for delivery to its final are assumed to operate destination. Drayage is Triple-trailer combinations with 53-foot and 28.5-foot assumed to be along the are allowed direct access, trailers. TPDs are assumed most direct route off the under a State-issued to operate with two 53-foot network between the permit, to and from the trailers. The eight-axle B- shipper or receiver and the network without train is assumed to operate network. disconnecting the trailers.

III-22 lengths longer than 53 feet Termination of State H. R. 551 Scenario that were in lawful Determination of operation in 1982. States Grandfather Rights would be prohibited from H.R. 551, “The Safe registering new trailers, H.R. 551 includes a Highways and containers or other cargo- provision, closely modeled Infrastructure Preservation carrying units longer than on the ISTEA LCV freeze, Act,” was first introduced 53 feet for operation on the which would codify and in 1994 during the 103rd Interstate and those classes freeze all Interstate System Session of Congress, and of qualifying NHS grandfather rights. The again in 1997, as H.R. 551, highways as designated by proposed legislation during the 105th Session. the Secretary of requires the FHWA to The bill would federalize Transportation. Existing publish a list of vehicles or certain areas of truck trailers, semitrailers and combinations which were regulation that are now other cargo units longer lawfully operating at State responsibilities. This than 53 feet or those weights over the Federal scenario is a subset of the manufactured up to one year Interstate weight limits Uniformity Scenario after the date of enactment before January 1, 1997. described earlier. would be allowed to This list would be by route, operate indefinitely. commodity and weight. H.R. 551 contains three provisions related to This section of H.R. 551 is Federal TS&W limits: (1) intended to prevent the it would phase out trailers proliferation of very long longer than 53 feet, (2) it semitrailers. It has been would freeze State asserted that trailers longer grandfather rights, and (3) than 53 feet are relatively it would freeze weight more dangerous than shorter limits (including divisible trailers because of off- load permits) on non- tracking and swing-out lane Interstate portions of the encroachment. Further, NHS. However, only the some maintain that if these first provision was longer trailers jackknife analyzed. they are more likely to hit other vehicles. H.R. 551 Provisions and Background As shown in Table III-7, ten States currently permit the Phase Out of Trailers operation of semitrailers Longer than 53 Feet that are over 53 feet long. Six of the ten States limit The proposed legislation the operation of these would repeal provisions of longer trailers to the NN the STAA of 1982 which (which includes the grandfathered all trailer Interstate).

III-23 Table III-7. States Routinely Allowing Semitrailers Longer vehicle weights. Than 53 Feet Scenario Specifications State Length Limit Figure III-15 summarizes Alabama 57 feet key provisions of this scenario. The scenario has Arkansas 53 feet 6 inches been proposed to preclude Arizona 57 feet 6 inches States from raising their TS&W limits Colorado 57 feet 4 inches prospectively. A review of Kansas 59 feet 6 inches changes in State TS&W laws over the past ten years Louisiana 59 feet 6 inches revealed that such New Mexico 59 feet 6 inches increases have not occurred except in a Oklahoma 59 feet 6 inches limited number of cases Texas 59 feet involving specific commodities or truck Wyoming 60 feet configurations. For example, the kinds of divisible load permits have State authority to determine expanding Federal authority not changed appreciably weight limits under the to regulate truck weight over the last ten years. 1956 or 1975 grandfather limits. The freeze would However, the number of clause—as provided for by also apply to divisible load permits issued has the Symms Amendment permits. At present, States increased (see Table III-8). (see Figure III-14)—would establish vehicle weight be repealed. The freeze limits for their highways This observation is not would not prohibit any of other than those on the surprising since the ISTEA the existing exceptions to Interstate System. freeze has been in place Federal limits, but would since 1991. The analytical constrain States to the For roads, where vehicle implication, in terms of this existing limits. This would weight limits are study, is that the only apply to both permitted and determined by the Federal feature of the H.R. 551 non-permitted limits. government, the proposed proposal that can be weight limit freeze would modeled is the limitation Freeze on National increase the number of road on trailer length. It is Highway System miles from 44,000 miles Weights (the current Interstate System) to almost 156,000 H.R. 551 proposes a freeze miles (the NHS). This on non-Interstate NHS proposal would effectively weight limits, greatly eliminate all State flexibility to allow higher

III-24 Figure III-14. The Symms Amendment

The Surface Transportation Assistance Act (STAA) of 1982 provided more uniform truck size and weight standards across the country by requiring States to raise weight limits that were lower than the Federal standard. Prior to this there was no Federal legislative provision that would prevent the States from enforcing lower limits.

The STAA of 1982 also gave States added authority to determine their own grandfather rights. A provision introduced by Senator Symms, allowed the States to determine which “vehicles or combination thereof... could be lawfully operated within such State on July 1, 1956.” Some States have argued, based on this legislation that they are the sole arbiters of their grandfather rights. As a result of this legislation, ten States have claimed grandfather

Table 8. State Permitting of Overweight Loads – 1985-1995

Divisible Divisible Divisible Nondivisible Nondivisible Nondivisible Total Year Single Multiple Total Single Multiple Total Permits

1,272,869 1985 62,810 90,832 153,642 1,072,776 46,451 1,119,227

1,359,068 1986 53,976 96,193 150,169 1,149,625 59,274 1,208,899

1,358,364 1987 51,824 102,759 154,583 1,136,649 67,132 1,203,781

1,390,710 1988 64,955 112,801 177,756 1,151,732 61,222 1,212,954

1,485,544 1989 67,194 136,267 203,463 1,205,394 76,687 1,282,081

1,623,590 1990 73,270 140,697 213,967 1,321,261 88,362 1,409,623

1,650,166 1991 163,228 160,914 324,142 1,259,176 66,848 1,326,024

1,787,258 1992 184,711 162,040 346,751 1,347,773 92,734 1,440,507

1,758,384 1993 160,847 166,865 327,712 1,325,802 104,870 1,430,672

1,898,427 1994 157,114 198,236 355,350 1,426,143 116,934 1,543,077

2,030,531 1995 169,013 211,502 380,515 1,543,270 106,746 1,650,016

Source: FHWA Annual Inventory of State Practices, Overweight Vehicles–Penalties and Permits, FY85-FY94; and FY95 Annual State Certifications

III-26 Figure III-15. H.R. 551 Scenario

Main Features

• Phases in elimination of Two to four-axle single unit truck semitrailers over 53 feet long Current law at 54,000 pounds to 70,000 pounds • Assumes status quo weights

Available Highways

• National Highway System Five to six-axle tractor-semitrailer Current law at 80,000 pounds to 100,000 pounds Access Provisions

• Current Federal and State provisions

Five to six-axle STAA double trailer combination Current law at 80,000 pounds

impossible to predict what posed legislation would not The Network States might do in the impact other equipment. future with respect to This scenario does not changing their TS&W Because the longer trailers include any change to the limits, since a meaningful in use today would be status quo. It is notable, historical trend does not grandfathered, the analysis however, that an NHS exist. assumes that these trailers weight-limit freeze would would remain in use not create an incentive to The Vehicles indefinitely. The analysis increase weight on roads also assumes that the off the NHS because H.R. 551 would phase out additional increment of relatively little freight is all semitrailers longer than freight that longer trailers transported between origins 53 feet. These trailers are would have hauled in the and destinations for which used primarily to transport 2000 analysis year will non-NHS routes are low-density freight that have to be carried in the practical. benefit from the additional shorter, 53-foot trailers. cubic capacity. The pro- Access Provisions

III-26 Figure III-16. Triples Nationwide Scenario

Main Feature

Ÿ Broad national operation of triple-trailer combinations and new 2-S1-2-2 weight limits for triple-trailer combinations

Seven-axle triple-trailer combination Available Highways 132,000 pounds (maximum) Ÿ 65,000-mile system

Access Provisions

Ÿ State issued permits

key provisions of this trailer combinations. The Current Federal and State scenario. reader is referred to access requirements would Chapter II for a discussion remain in effect. The Vehicles of this network.

The Triples Nationwide Access Provisions Triples Nationwide Scenario focuses on the Scenario seven-axle triple-trailer Current State access combination which will be provisions would remain in permitted to operate effect. Triple-trailer This scenario, a subset of nationwide at a GVW of combinations are assumed the LCVs Nationwide 132,000 pounds. to have direct access to and scenario, would permit the from the network without operation of triple-trailer The Networks disconnecting the trailers, combinations across the in accordance with State country. This scenario was tested issued permits. Therefore, using the 65,000-mile there is no requirement for Scenario Specifications analytical network staging areas. developed to test triple- Figure III-16 summarizes

III-27