Safe, Strategic Use of Highway Capacity

- Final Paper -

Paul Grant QMB Marketing Lindsay Transportation Solutions 180 River Road Rio Vista, CA 94571 USA Phone: (209) 652-5667 Fax: (707) 374-6801 [email protected]

Paper abstract: By the year 2025, there will be an additional one billion people on the planet, most with transportation and mobility needs. This will place significant additional stress on existing infrastructure in many countries around the world, particularly in cities where transportation systems are already gridlocked by the current motorist population. This impact has significant value: in the United States, the cost of congestion hovers above US $100 billion, and Europe has a current congestion cost of over €200 billion.

One solution to this problem is to create new capacity by building additional highway lanes, but this can be extremely expensive. The FHWA reports that new urban freeway construction can cost US$10 million per lane mile or more. A different, less expensive approach that is gaining popularity around the world is creating managed lanes facilities, where lane management strategies are adopted to regulate demand, reclaim unused lane capacity, and calm traffic patterns to make the most effective and efficient use of the roadway for both freeways and arterials. Managed lanes can mitigate congestion, raise funds for required maintenance and repairs for the facility, and improve the quality of life for the road users.

Safety cannot be sacrificed to reach these goals, and there are many instances where concrete barrier separation between lanes is required for the safest possible operation of the managed lanes facility. Permanent concrete barrier can be used, but it is inflexible by nature and often impedes the agency’s ability to respond to changing traffic patterns on a daily basis or over an extended period. Another solution is moveable concrete barrier, which has the flexibility to reconfigure highway and arterial lanes in real time, while still providing the security and safety of positive barrier protection. Moveable barrier installations around the world report increases in both safety and capacity.

Safe, Strategic Use of Highway Capacity

1. Introduction By the year 2025, there will be an additional one billion people on the planet, most with transportation and mobility needs. This will place significant additional stress on existing infrastructure in many countries around the world, particularly in cities where transportation systems are already gridlocked by the current motorist population. This impact has a significant price tag: in the United States, the cost of congestion has hovered above US $100 billion for several years, and Europe has a current congestion cost of over €200 billion annually.

One solution to this problem is to create new capacity by building additional highway lanes, but this can be extremely expensive. The FHWA reports that new urban freeway construction can cost US $10 million per lane mile, and other estimates put the cost at 5 to 10 times that amount. Additional challenges to building new general purpose lanes include right-of-way constraints and environmental concerns that add years to a project timeline. A different, less expensive approach that is gaining popularity around the world is creating managed lanes facilities, where lane management strategies are adopted to regulate demand, reclaim unused lane capacity, and calm traffic patterns to make the most effective and efficient use of the roadway for both freeways and arterials. An effective managed lanes facility seeks to meet regional mobility, safety, and financial goals to improve the driving experience and quality of life of the users and the surrounding community. The results of these efforts can help mitigate congestion, generate additional revenue for required maintenance and repairs for the facility, and lower the number of fatal and serious injury accidents.

2. Managed Lanes Strategies

The definition of a managed lanes facility may vary from one agency to the next. The FHWA defines a managed lanes facility as “highway facilities or a set of lanes where operational strategies are proactively implemented and managed in response to changing conditions.”(1) Managed lanes applications typically fall into one of three categories: capacity redistribution, vehicle eligibility, and pricing. Some managed lanes facilities incorporate multiple strategies for a greater degree of operational control.

Capacity Redistribution: Some managed lanes facilities will employ a flexible or variable median to give more lanes to the peak traffic direction based on daily tidal traffic flow. Often times the agency goal is only to reclaim unused capacity or to balance traffic flow, and the additional lanes are unrestricted general purpose lanes. This strategy is common on bridges where traffic flows into the city in the morning and out of the city in the evening, with excess capacity available on the non-peak traffic side. The roadway reconfiguration is typically accomplished through overhead lighting gantries and painted lane buffers, and/or by manually shifting plastic delineation back and forth as a lane separator. While effective at increasing lane capacity, these systems are candidates for severe crossover accidents.

Lane shift using overhead lights and paint buffers Lane shift using plastic delineation

Vehicle Eligibility: Another popular managed lanes strategy is to allow certain vehicles to make use of the managed lanes while restricting others. The most common example of this is the High Occupancy Vehicle (HOV) lane. The HOV lane imposes a minimum number of vehicle occupants (usually two or three) for access to the managed lanes during specific times of certain days of the week, essentially providing travel time advantages to high occupancy vehicles. This strategy encourages ridesharing and van pools, reducing the number of vehicles on the roadway and provides benefits to all users. Bus Rapid Transit (BRT) systems also benefit from vehicle eligibility strategies. BRT systems that use the HOV lanes or dedicated Bus Only Lanes can offer faster, more reliable transit times for users, building confidence in the system and increasing ridership. Motorcycles and low emission vehicles are also commonly allowed to use restricted lanes.

Concurrent flow HOV lanes Bus Rapid Transit (BRT) lanes

Pricing: This strategy implements fixed or variable tolling costs associated with the use of the managed lanes. These programs generate revenue while allowing single passenger vehicles to use the express lanes. Tolling is often combined with vehicle eligibility restrictions to create HOT (High Occupancy/Toll) lanes, so that non-eligible vehicles may use the HOV lanes for a fee. Pricing often varies during the day to manage lane speed and throughput. Revenue generated by pricing lanes can be a great benefit to the facility.

Variable pricing in the I-15 Express Lanes 3

3. Safety Concerns for Managed Lanes

The safety of the motoring public cannot be compromised by the implementation of a managed lanes facility. Agencies must consider how the new lane configurations will affect the overall safety of the motoring public through the facility. Typically, there are three strategies that agencies can use to protect motorists from differences in speed and driver behavior between the managed lanes and the general purpose lanes: no separation (called “continuous access”), buffer separation, and barrier separation. Additional consideration is then given to whether the managed lanes are concurrent flow or contraflow.

The United States has a wide range of managed lanes facilities created and operated by the various states. California’s HOV strategies are divided regionally: in Northern California, HOV lanes are predominately continuous access, while Southern California operates predominately buffer separated lanes. The difference between the two lies in the opportunity for ingress and egress from the HOV lane. Continuous access lanes have no paint buffer or delineation of any kind, and users may move in and out of the managed lanes at will. Buffer separated lanes have a paint buffer and/or plastic delineation to separate the managed lanes from the general purpose lanes, and access to the managed lanes is allowed only through specific ingress and egress locations.

Continuous Access HOV lane Buffer Separated HOV lane

While many agencies choose to implement buffer separated lanes as a method of increasing safety in the corridor, a recent joint study by the UC Berkeley Traffic Safety Center and Caltrans determined that limited access facilities offer no safety advantages over continuous access. In fact, the study showed that limiting ingress and egress from the managed lanes to the adjacent general purpose lane resulted in higher combined collision rates for both lanes when compared with continuous access.(2)

While these results may have surprised some agencies, it is no surprise that both strategies are inferior from a safety perspective when compared to barrier separated lanes. These may be concurrent, reversible, or contraflow lanes that are separated from the general purpose lanes by concrete barrier. The Texas Transportation Institute found that during peak traffic periods, traffic in HOV lanes can move as much as 35 mph (56 km/h) faster than the general purpose lanes. While increased speed in the HOV lane is certainly a primary agency goal for an HOV lane, the speed differential contributes to an increase in the injury crash rate for non-barrier separated lanes and the adjacent general purpose lane between 41% and 56%. The study also found that there was no injury accident rate increase in barrier separated lanes.(3) The data implies that a major factor in the accident increase is shoulder width; most barrier separated lanes are designed with wider shoulders

4 for incident management, while many buffer separated lanes have been converted from existing highway shoulders.

Limited access HOV, no shoulders Access abuse contributes to accidents Barrier separated lanes: wider shoulders

Barrier separation between lanes becomes even more critical when contraflow lanes are created. For the contraflow lane application, traffic from one side of the roadway is allowed to cross over to the other side and run “contraflow” to opposing traffic. This configuration is extremely dangerous when paint, lighting gantries, and plastic delineation are used to separate lanes, and positive barrier protection should be required to avoid head- on, crossover accidents.

A city bus, unprotected at freeway speeds A barrier separated contraflow lane

Positive barrier separation is critical anytime opposing lanes of traffic run adjacent to one another, but traditional concrete barrier is not a flexible asset, and its use will limit the options for a managed lanes facility. A 2009 study of the I-10 Katy Freeway through Houston, Texas investigated whether the barrier separated reversible lane in the center of the freeway was still more useful than the two general purpose lanes that could have fit in the same space. The study found that while the reversible lane was the best solution during the earlier part of the decade, an increase in overall traffic congestion created a condition where the general purpose lanes would have better served the highway users because the inflexible configuration of the HOV lane was no longer optimal.(4) This lack of flexibility from the barrier separated lane was resolved with expensive new construction to create additional general purpose and HOV lanes.

4. Managed Lanes Benefits with Moveable Barrier

On the I-30 Freeway in Dallas, Texas, a different and more flexible approach is used to create managed lanes. A moveable concrete barrier is stored next to the median on both sides of the freeway, and during the morning commute into the city, the barrier on the off- 5 peak side is moved out one lane plus a shoulder area by a Barrier Transfer Machine (BTM), and eligible vehicles are allowed to cross over to the other side of the freeway and run contraflow to traffic, while being protected by the concrete barrier. When the peak period ends, the barrier is shifted back to the median and the lane is returned to concurrent flow traffic. This process is repeated on the other side of the freeway for the evening peak commute. By using a moveable concrete barrier, the I-30 can be reconfigured on a daily basis for a fraction of the cost of building the two additional lanes with traditional construction methods. The I-30 HOV lanes save 15,000 commuters an average of 14 minutes per day, and carpools and bus ridership increased 300% and 38% respectively.(5) Average vehicle occupancy in the HOV lane is 2.9, compared to the general purpose lanes which average 1.1 riders per vehicle. With a Benefit to Cost ratio of 6.5:1, this system has helped TXDOT achieve goals in mobility, safety, reliability, air quality, and economics, and it has been expanded three times since the initial installation for a total system length of 22 miles.

The BTM opens a lane on I-30 in Dallas, TX The I-30 HOV lane runs contraflow with barrier protection

Moveable barrier also functions as a “moveable median” on bridges, tunnels and viaducts where few center structures exist. In these cases, one wall of moveable barrier separates opposing lanes of traffic, and the barrier is shifted back and forth one or more lanes to provide more capacity to the peak traffic side. In New Zealand, the Auckland Harbour Bridge used lights and plastic delineation to manage its four center lanes, but in the final five years of this configuration there were 128 injury accidents, including 10 fatalities.(6) The lighting and delineation system was replaced with a moveable median barrier, and in the 23 years that the system has been in operation, there has not been a single crossover injury accident. The system was upgraded after 20 years, and now the median transfer that took 45 minutes with the original system is accomplished in just 20 minutes.

Before, lights and cones separated the bridge lanes Now, moveable barrier safely reconfigures lanes

Another innovative use of moveable barrier for managed lanes is creating outside BRT lanes on arterials. Victoria Road in Sydney, Australia, is a six-lane arterial. Cars were allowed to park in the outside lane to access businesses, bringing the useful number of lanes down to two in each direction. This created difficulties for the Bus Transit system, and bus travel times were long and unreliable. The Regional Transit Authority required a solution that improved the BRT system without taking additional lanes from motorists, all while keeping a solid center median to discourage pedestrians from crossing the street except at approved locations. The solution was to install a moveable median barrier that could reconfigure the roadway to add a lane to the peak morning direction, giving the peak direction four lanes rather than three. The outside lane was then converted to a Bus Only lane between 5:30 and 9:45 am. Vehicles were not allowed to park in the outside lane during this time. After the peak traffic period, the extra lane would be restored to traffic and the road would be returned to a 3/3 configuration. The agency goal of saving 18 minutes on each bus trip during the morning peak was realized on the first day of system operation, increasing bus schedule reliability and reducing transit times without any negative impact on passenger vehicle traffic.(7)

Moveable barrier quickly reconfigures the roadway BRT travel time and reliability goals were met on Day One

5. Combining Strategies to Create Dynamic Highways

Facilities that employ multiple lane management strategies can become true “Dynamic Highways” capable of meeting regional transportation needs for years to come. In San Diego, California, the I-15 Express Lanes encompass a 20-mile, state of the art facility. The Express Lanes began in 1988 as an eight-mile facility with two reversible center lanes for High Occupancy Vehicles. These lanes were separated from the general purpose lanes with concrete barrier. Between 1996 and 2006, average daily traffic through the corridor increased 100%, and HOV usage increased 45%. The current facility, built in three stages at a total cost of over US$1 billion, has four barrier separated center lanes, with a moveable median barrier managing the lanes in a 1/3, 2/2, or 3/1 configuration. The center lanes are now HOT lanes, allowing single passenger vehicles to use the facility for a fee. The pricing structure is designed to maximize free-flow travel, and the cost fluctuates in real time based on location, miles traveled, and congestion hotspots, with total revenue estimated between US$7 million and US$9 million per year. Direct access ramps allow buses from a new BRT system to bypass freeway ramps and travel directly into and out of the Express Lanes. The success of the I-15 Express Lanes serves as a model for other agencies to design managed lanes systems from the ground up to create the Dynamic Highways of the future.

Direct access ramps for Express Lanes users and BRT Four barrier separated center lanes with a moveable median

6. Summary

As the costs of congestion and construction reach record levels around the world, highway agencies and concessionaires must develop innovative approaches to reach their mobility, safety and economic goals. Creating managed lanes is a viable option in many instances, and when properly designed, constructed and operated, these facilities can mitigate congestion, generate additional revenue, and improve quality of life for the road users and surrounding communities.

Safety cannot be sacrificed to reach these goals, and agencies must review appropriate safety options for each facility. Concurrent flow lanes may not require barrier separation in all cases, but high speed contraflow applications must have positive barrier protection. Static barrier separated lanes with wide shoulders combine the safety of positive protection with fixed operating costs, but they do not provide the flexibility required in many instances. Moveable barrier systems have a slightly higher operational cost than static barrier systems, but they allow agencies to reconfigure the roadway in real time, and moveable barriers are a reusable asset that can be redeployed to a different facility if traffic patterns change. Moveable barrier should also be considered when designing BRT lanes, as free flow and lack of constriction points is critical to a BRT system. Static and moveable barrier can also be combined to create a “freeway within a freeway” for the ultimate in safety and flexibility.

7. References

(1) Department of Transportation, Federal Highway Administration. 2008. Managed Lanes: A Primer.

(2) Jang, Kitae, et al. 2008. Safety Evaluation of High-Occupancy Vehicle Facilities in California. Intellimotion, Vol. 14, No. 2.

(3) Texas Transportation Institute. 2004. Crash Analysis of Selected High-Occupancy Vehicle Facilities in Texas.

(4) Burris, Mark and Lipnicky, Kevin. 2009. HOV Lane Benefits. Texas A&M University.

(5) Bain, Robert. 2002. Moveable Barrier Technology – the Key to the Dynamic Highway. Traffic Engineering & Control Magazine.

(6) Hawkins, N.V. 1995. Fatal Accidents Eliminated by a Moveable Lane Barrier. University of Auckland.

(7) Inner West Busway Along Victoria Road. 2011. New South Wales Regional Transit Authority. www.rta.nsw.gov.au.