Chapter 3: Transportation Network Profile Introduction
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Chapter 3: Transportation Network Profile Introduction After using the socioeconomic data collected in Chapter 2 to model travel the activities of the area’s residents, the next step is to study the transportation network on which these activities will take place. The primary goal of the chapter is to assess the current condition of the transportation network in the DMATS area. The chapter includes data on the area’s roadways including traffic volumes, levels congestion, and vehicle crashes. The chapter also focuses on other modes of transportation including public transit, bicycle and pedestrian, freight, and air travel. The final section of the chapter includes information on some special transportation initiatives currently being undertaken within the area. Roads The predominant transportation system in the DMATS area, as in the rest of the United States, is a network of streets and highways that carry automobiles and trucks. These roadways accommodate the travel needs of local residents businesses and travelers from outside the area. The roads section of the chapter describes the roadway system in the DMATS area in terms of its functional classification, existing capacity, congestion, and safety. Functional Classification Functional classification describes roadways based on the type of service they provide. Roadways provide two basic types of service: land access and mobility. The degree to which a roadway provides access and/or mobility determines its functional classification. The key to planning an efficient roadway system is finding the appropriate balance between mobility and accessibility. Principal Arterial roadways primarily serve a mobility function with minimal land access. The primary purpose of principal arterials is the rapid movement of people and goods for extended distances. Principal arterials are high capacity, high speed roadways with restricted access. US Highway 20 is an example of a principal arterial in the DMATS area. Minor Arterials interconnect with and augment principal arterials. Minor arterials within urban areas serve inter-community trips of moderate length. Although the primary use of the minor arterial is mobility, this functional class provides more land access than a principal arterial. John F. Kennedy Road in the City of Dubuque is a local example of a minor arterial. Collector streets channel trips between the local street system and the arterials. Collectors serve a balance between mobility and land access. Parking and direct driveway access to the street are typically allowed on collectors. Collectors are usually wider, have higher capacity, and permit somewhat higher speeds than the local street network Collectors are broken down into two categories Major Collectors and Minor Collectors. Chaney Road in the City of Dubuque is a local example of a collector street. Local Streets primarily provide local land access and offer the lowest level of mobility. Characteristics of local streets include uncontrolled intersections, posted speed limits of 25 miles per hour or less, and few restrictions on parking. Local streets are not a significant consideration in metropolitan planning and this plan does address them in any systematic fashion. 1 The Federal Highway Administration uses functional classification to determine if a roadway is eligible for federal funds. Federal-aid eligible routes include: Principal Arterials, Minor Arterials, Major Collectors, and Urban Minor Collectors. Rural Minor Collectors and Local Streets are not Federal-aid eligible. Figure 3.1 breaks down DMATS area routes by classification, and Figure 3.2 maps the routes. Figure 3.1 DMATS Roadway Functional Classification Annual Average Vehicle Miles Route Classification Lane Miles Daily Traffic Traveled Principal Arterials 128.2 3,741,294 990,743 Minor Arterials 52.7 4,030,103 368,510 Major Collectors 69.6 829,562 198,680 Rural Minor Collectors & Local Streets 87.3 624,724 126,594 Source: Iowa DOT, Illinois DOT, & Wisconsin DOT Figure 3.2 Roadway Functional Classification Source: Iowa DOT, Illinois DOT, & Wisconsin DOT 2 Traffic Volume Transportation planners use average annual daily traffic (AADT) to measure the use of the roadway system. AADT is an annualized measure of traffic volume on a road segment. AADT numbers are based on traffic counts that local and Iowa DOT engineers periodically collect on area roads. Traffic counts provide onetime “snapshot” views of traffic on area roads that traffic engineers then extrapolate into an annualized daily average using a mathematical process. This plan reports 2010 traffic data as 2010 is the base year for the DMATS Travel Demand Forecast Model. Figure 3.3 displays the 2010 traffic volumes from the DMATS travel demand forecast model network. Figure 3.3 2010 Traffic Volume Source: Iowa DOT Traffic Counts, DMATS Travel Demand Forecast Model 3 Level of Service Level of service (LOS) is a qualitative measure describing conditions within a traffic stream, based on speed and travel time, freedom to maneuver, traffic interruptions, comfort, and convenience. LOS is determined by calculating the Volume to Capacity (VC) ratio, where the traffic volume, observed or forecasted, is divided by the estimated capacity of the roadway. LOS “A” represents complete free flow of traffic, allowing traffic to maneuver unimpeded. LOS “F” represents a complete breakdown in traffic flow, resulting in stop and go travel. Figure 3.4 shows a map of level of service and traffic volume for the DMATS area and Figure 3.5 includes a table of road segments that have a LOS value of D, E, or F. Figure 3.4 2010 Level of Service Source: State DOT Traffic Counts, and DMATS Travel Demand Forecast Model *V/C thresholds for LOS Categories A <= 0.51, B <= 0.67, C <= 0.79, D <= 0.9, E <=1, F >= 1 Figure 3.5 Level of Service 4 LOS D LOS E LOS F University Ave Asbury Rd US 20 / Dodge St US 20 / Dodge St Delhi St Kerrigan Rd Sinsinawa Ave Locust St S Bluff St Asbury Rd US 20 / Dodge St University Ave US 61 Badger Rd Sinsinawa Ave Pennsylvania Ave US 61/151 Asbury Rd Cedar Cross Rd W 9th St Vehicle Crashes DMATS is committed to improving transportation safety through the goals and objectives of the DMATS LRTP. Reducing vehicle crashes, and the injuries and fatalities that result from crashes, is a top priority for DMATS. Vehicle crash data was acquired from the Iowa Department of Transportation for the Iowa portion the DMATS region. DMATS was unable to acquire data for the Illinois and Wisconsin portions of the region. The data includes vehicle crashes with other vehicles, pedestrians, bicycles, and fixed objects. DMATS has mapped the crashes to illustrate the distribution of fatal and major injury crashes and locations experiencing the most crashes. DMATS uses these maps along with input from local engineers and law enforcement to help identify locations that may need safety improvements. DMATS conducts a more detailed safety analysis through the LRTP project ranking process. Chapter 9 of this plan details the project ranking process. Figure 3.6 maps the location of all fatal and major injury crashes that occurred from 2009 – July 2014. The 17 fatal crashes occurred during this time period seem to be spread across the region with some clustering in downtown Dubuque and on more rural sections of the region’s state highways. The 96 major injury crashes from this time are also spread across the region but seem to be more frequent on the regions arterials and major collectors. Higher traffic volumes on these roadways likely play a role in the higher occurrence of fatal major injury crashes. Figure 3.6 Fatal and Major Injury Crashes (Iowa Only) 5 Source: Iowa DOT Crash 2009 –July 2014 To illustrate where clusters of crashes have occurred, 30 foot buffers were created in GIS around all crash locations in Iowa. Any overlapping buffers were then merged together to create a cluster region, and the number of crashes occurring in each cluster region was calculated. Figure 3.7 illustrates which areas had the highest concentration of crashes in the five year period. For better clarity, all clusters with fewer than 20 crashes in them were excluded from the map. The ten clusters with the most total crashes are listed in Figure 3.8. Figure 3.7 Crash Clusters by Number of Crashes 6 Source: Iowa DOT Crash Data 2009-2014 Figure 3.8 Top Ten Crash Locations by Number of Crashes Rank Crashes Location 1 82 US 20 / Dodge St & Iowa 946 2 64 US 20 / Dodge St & Wacker Dr 3 56 US 20 / Dodge St & Iowa 32 / NW Arterial 4 56 US 20 / Dodge St & Hill St Ramp WB 5 53 E 20th St & White St 6 51 Pennsylvania Ave & John F Kennedy Rd 7 50 US 20 / Dodge St & Cedar Cross Rd 8 50 Asbury Rd & Iowa 32 / NW Arterial 9 45 Pennsylvania Ave & Iowa 32 / NW Arterial 10 45 E 14th St & White St Using the same clusters with 20 or more crashes, the areas with the most severe crashes were examined. Using the 1 through 5 severity values recorded in the crash database (1 = fatality, 2 = major injury, 3 = minor injury, 4 = unknown injury, 5 = property damage only), an average score was calculated to produce a severity score. Lower severity scores indicate more severe crashes. Figure 3.9 maps the 7 results of the average severity score calculations, and Figure 3.10 lists the top ten crash clusters by severity score. Figure 3.9 Crash Clusters by Severity Score Source: Iowa DOT Crash Data 2009-2014 Figure 3.10 Top Ten Crash Locations by Severity Score Rank Severity Score Location 1 4.3333 Loras Blvd & Iowa St 2 4.36 Iowa 32 / NW Arterial & US 52 3 4.4 Iowa 32 / NW Arterial & John F Kennedy Rd 4 4.4063 Loras Blvd & Locust St S 5 4.4167 Old Highway Rd & Seippel Rd 6 4.5 E 17th St & Jackson St 7 4.5172 E 22nd St & Central Ave 8 4.52 Asbury Rd & Iowa 32 / NW Arterial 9 4.5217 Loras Blvd & Main St 10 4.5333 E 14th St & White St Transit 8 Transit service connects many DMATS area residents to work, school, and other important activities.