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Out of Control Policy Blog Archives: 9.2.12–9.8.12

Where BRT with Queue Jumpers Works: DeKalb County, GA

DeKalb County, Georgia features an excellent example of a Bus-Rapid-Transit (BRT) line with traffic signal priority and queue jump lanes. The partnership of DeKalb County, the Metropolitan Atlanta Rapid Transit Authority (MARTA), the Georgia Department of Transportation (GDOT) and the Federal Transit Administration (FTA) has effectively implemented BRT on the major arterial of Memorial Drive. 

As detailed yesterday, (BRT) is a transit line that can bypass congestion. BRT service operates in a dedicated lane or receives signal priority via queue jumpers. With the exceptions of New York City, the District of Columbia, downtown Chicago, and central San Francisco, the frequency of bus service is not high enough to dedicate an entire lane to buses. As a result dedicating an existing lane to buses is an inefficient use of the roadway. Further, it is sure to enrage automobile drivers. Since these corridors have fewer than 60 buses an hour or less than one bus a minute, the best solution for most places is offering signal priority via queue jump lanes

In priority signaling, a bus has special equipment that alerts a traffic signal that it is approaching the intersection. In some situations, the traffic signal will turn green in a matter of seconds so the bus does not have to stop for a red light. In other situations the bus gets a priority green; a priority green gives the bus a 5-20 second head start over other vehicles. BRT systems with priority signaling typically have either a dedicated lane at intersections or share traffic with the right-lane. This allows the bus to jump ahead of traffic when the light turns green. 

DeKalb County deputy director of Engineering Peggy Allen detailed the Memorial Drive service in the Partnering for Improved Transit Service session at last month’s Institute of Transportation Engineers Annual Meeting and Exhibit.  DeKalb County in the Atlanta region first implemented traffic signal priority in 1999 along busy Candler Rd. Traffic signal priority gives preference to local buses at 17 major intersections. Then, DeKalb County worked with MARTA, GDOT and FTA to implement the Memorial Drive Bus-Rapid-Transit service with signal priority at 27 intersections. 

The Memorial Drive project is being evaluated against three main goals: improving air quality, providing cost-effective transit service and reducing traffic congestion. The DeKalb County project features signal prioritization, queue jumper lanes at intersections, electronic information displaying bus arrival times and multi-door boarding. There are two BRT services that operate along much of the 5-mile corridor during rushhour. Each operates every 10 minutes. 

The BRT vehicles have special radio/GPS emitters. The emitter sends speed, heading and position information that is updated each second. The data sent by the emitter is received by the radio/GPS receiver, which is located near the signalized intersection. If the vehicle is approaching while the signal is green, the detector prompts a sequence within the controller that provides for additional green time to get the vehicle through the intersection. This allows all vehicles in parallel lanes to clear the intersection as well.

If the BRT vehicle is approaching the intersection on a red signal, the traffic signal phases for the side streets revert to minimum cycle times to allow a green signal for the approaching vehicle as soon as feasibly possible in the timing sequence. One unique aspect of the system is that it maintains signal coordination along the corridor.

Several of the intersections make use of queue jumpers. The concept allows the bus, which is in a restricted travel lane, to receive a green indication at the traffic signal while other vehicles remain at a stop condition at the same intersection, thus giving the bus priority in the queue. 

In order to differentiate between the signal indications for the normal traffic signal phases and the queue jumper signal phase, the two-lens light rail transit signal indication was used as the signal indication in the BRT lane. Both the go and the stop indications are white, which prevents any possible confusion for motorist in the travel lanes parallel to the queue jumper lane. Additionally, a “Bus Signal” sign was displayed at the intersection adjacent to the light rail transit signal indication to further differentiate them from the usual signal indications. 

Having the appropriate traffic signal timing plan in place is critical to ensuring the proper operation of the system. Prior to implementing the transit signal priority system the morning rush hour timing plan had a cycle length of 150 seconds and used eight phases of the controller. After implementing the system the cycle length for the corridor was increased to 160 seconds. Additionally, the queue jumper installation necessitated the addition and utilization of a ninth phase, separate from all of the other phases in the cycle. 

Preliminary data show that this BRT line has decreased congestion by more effectively using the roadway and by providing a more reliable, more used bus route. At the same price as a local bus, the Memorial Drive BRT lines offer better, more reliable service at a low price. Finally, improved travel speeds for both cars and buses has reduced pollution. While ridership is very strong, the service could be improved further if queue jump lanes were built at the remaining intersections. The Memorial Drive corridor is similar to other congested arterial corridors around the nation. If the service works in DeKalb County it can work most everywhere else.

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Local Bus Service is not Bus-Rapid-Transit

At last month’s 5th national Bus Rapid Transit (BRT) conference one of the key topics focused on which types of bus services qualify as BRT. While most transit practitioners think that BRT service must either offer a dedicated lane or some form of signal priority, some metro areas are branding any type of bus service BRT. This could confuse riders and limit the popularity of BRT. 

Bus-Rapid-Transit (BRT) is a popular transit technology used extensively throughout the world. Similar to light-rail BRT can operate in either a dedicated lane or in mixed traffic. However, light rail typically relies on an overhead wire for power. As a result, LRT is limited to certain corridors and certain lanes in a corridor. As BRT receives its power from an electric, natural gas, diesel, or combustion engine it can travel on any street. 

However, BRT differs from local and express bus as well. BRT vehicles have a system that allows them to bypass traffic congestion. This is typically a dedicated lane or priority signaling. In a dedicated lane system one lane of traffic in each direction is prioritized for buses. Sometimes these lanes are in the middle of the road separated from other traffic. Other times the lane is the right or left lane of the existing roadway. Sometimes BRT buses share left or right turn lanes with cars. In priority signaling a bus has special equipment that alerts a traffic signal that it is approaching the intersection. In some situations the traffic signal will turn green in a matter of seconds, so the bus does not have to stop for a red light. In other situations the bus gets a priority green; a priority green gives the bus a 5-20 second head-start over other vehicles. BRT systems with priority signaling typically have either a dedicated lane at intersections or share traffic with the right-lane. This allows the bus to jump ahead of traffic when the light turns green. 

BRT is different from local or express buses. Local buses have numerous stops, often every 1/8 mile or less. These slow routes are designed to provide easy-access to everybody in the neighborhood. Express buses and limited-stop buses typically have fewer stops and a faster commute. Express buses have most of their stops in a small geographic area and travel some distance to an employment center. Limited-stop buses typically have consistent stops every ½ to 1 mile apart. Sometimes the terms are used interchangeably. Neither of these is BRT because buses do not receive priority compared to other vehicles in a corridor. 

All types of bus service are valuable. Many smaller communities may only need local-bus while the bigger communities may use local bus, express bus, and BRT. However, by calling any bus service BRT, agencies are distorting the concept of BRT. When consumers board a service labeled “BRT” that is really a local bus, their incorrect assumptions that BRT service is inferior to rail transit are reinforced. True BRT service is typically equal to or superior to rail service in speed, reliability and comfort. For most U.S. areas, BRT is the most realistic, rapid transit technology for the 21rt century. Delineating between regular bus and BRT service is essential.

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Latest Articles on Reason Foundation

California Legislature Mandates that "Public Service" Be Required for University Tenure

As Dan Walters reports in the Sacramento Bee:

A third element would be required in the hiring and promotion of faculty members. It's called "service." The specifics of Assembly Bill 2132 appear to give great weight to political, or at least semi-political, activities favored by those on the political left.

They include, in the words of a legislative bill analysis, "developing programs for underserved populations" and "outreach programs developed to promote cultural diversity in the student body."

The California State University system would be required to make "service" an element with teaching and the bill "encourages" the constitutionally independent University of California to include "service" in its evaluations.

It is a mistake for the state of California to "legislate" faculty requirements for tenure and promotion even at public universities. This is a one-size-fits-all policy and it politicizes "public service" and ignores legitimate reasons why in some disciplines public service may not be a priority for promotion. Is a faculty member completing research on breast cancer also required to complete public service in addition to their basic research? The emphasis on "public service" for future employment should be at the discretion of the University and faculty and should not be a matter for the California legislature to even consider, much less enforce. 

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Texas Transportation Institute Knows how to Measure Congestion

My friends at Streetsblog, upset with the MAP-21 highway bill that revoked the clause allowing entities to spend highway funds on transportation museums, are turning to the administrative rulemaking phase to create a new definition for congestion. Streetsblog is promoting a report written by Joseph Cortright for CEO for Cities. Mr. Cortright is also President of the Portland consulting firm, Impresa. 

At the Council for New Urbanism’s 2011 convention, Mr. Cortright debated Tim Lomax of the Texas Transportation Institute (TTI) on whether TTI’s Urban Mobility Report (UMR) accurately measure congestion. According to Cortright, “As a guide to understanding the problem’s of our urban transportation system and what to do about them, the Urban Mobility Report is a broken compass.”  

My colleague Bob Poole previously examined some of Cortright’s claims. Overall, Mr. Cortright makes several valuable points. Some members of the media do not fully understand the UMR report and over exaggerate the congestion issues. Also, while the report provides several policy recommendations it does not provide detailed recommendations for every city. Finally, due to data availability, TTI does not always have perfect data.

However, none of these issues is TTI’s fault. TTI does not control how the media reports the news. The UMR report has never claimed to offer detailed solutions for every metro area. And TTI partnered with INRIX several years ago to improve the data it uses. Further, TTI is constantly updating its methodology typically every 1-2 years to try to present a more accurate picture. 

Meanwhile let’s examine Mr. Cortright’s claims. Cortright argues that the travel time index is unreliable because it ignores the distance traveled. However, the UMR travel time index includes the delay per hour per traveler. Calculating the delay requires knowing the distance the driver travels. Distance is factored indirectly into the calculations. Results show that there is a strong relationship between the hours delayed and the travel time index. To use a real-world example, a commuter could be delayed on Lakefront Drive in Chicago or on I-77 in Charlotte but either way the driver is delayed. And while it takes 25.2 minutes to commute one-way work in Charlotte, it takes 31.0 minutes in Chicago. Further Cortright’s procedure to estimate trip lengths may be unreliable since it makes unproven assumptions about the data. Some of his points are valid, but his claims that TTI’s measures are flawed are not substantiated by the data. Cortright’s claim that his methodology is better is also not substantiated by the data. Chicago may have a better transit system than Charlotte, but that is not what TTI’s travel time index is trying to measure. 

What is really occurring is that Cortright is trying to use analytical methods to prove a new-urbanism ideal: Charlotte’s problem is that a higher percentage of residents live in suburbs. If only people lived closer to their workplaces in denser communities we could solve all congestion problems. 

However, this premise is not proven by facts. Further, it is unrealistic. Many households have two or three wage earners each with employment in a different area of the metropolis. Many of these families live in a specific suburb because it is closest to all three jobs. Second, in many metro areas the highest concentration of jobs is no longer in downtown. In some places it is no longer in the principal city. For example, the largest concentration of jobs in metro Atlanta and in fact in the entire southeast region is in the Perimeter Business district. This district is located in the suburban cities of Sandy Springs and Dunwoody not Atlanta. Third, many families consider other factors such as parks and schools. Unfortunately, many central cities have problematic schools and a major lack of park space. Parents number one concern is often their children, and the trade-off of a longer commute is worth it. Making congestion worse is unlikely to change their equation. Fourth, the central city is often the most expensive. Not everyone earns a six-figure salary and can afford to live there, even in an apartment or condo. Fifth, in some metros it is physically impossible, short of becoming Mumbai, for everyone to live very close to their workplace. This is particularly true for cities with a super dense concentration of jobs. 

In reality, Cortright is doing, what he encourages Lomax of TTI of doing. He is proposing a one-size fits all standard. Using Cortright’s logic we should never widen a highway, never increase the speed of transport and never consider the costs of travel time on society. Obviously this does not make sense. One reason for worsening congestion in most places including both Pre-World War II cities like Chicago and Post-World War II cities like Charlotte is that despite substantial population growth we have not added much new capacity. When more vehicles are forced to squeeze onto the same amount of road capacity, congestion is going to get worse. We have been using Cortright’s methods in many places and congestion has still worsened. While transit is part of the solution, decentralizing job centers and multi-worker households make creating a transit network more challenging. 

Some of Cortright’s claims are designed to appeal to economic development arguments. However, studies repeatedly show that traffic congestion leads to economic losses. And transit may offer a choice but it does not decrease congestion. At a certain level, the congestion has to be addressed. If a business is choosing between two cities equal in other respects, the business will almost always choose the city with less congestion. 

Further Cortright’s report fails to offer its own policy claims. But one solution, managed lanes, can benefit all transportation users not just drivers. Managed lanes, which TTI vigorously supports, enables mobility by charging a market price for travel instead of the one-size-fits all approach. Additional lanes can be part of the solution. But the biggest benefit is to transit users who have more reliable, frequent service. 

Streetsblog and other environmental groups have historically been weak on analytical claims. Their arguments have typically focused on normative issues such as urban design and non-economic based preference surveys. It is a step forward to see such an analytical report. Unfortunately, while the numbers add up, the underlying premise behind the numbers is flawed. It is not enough to provide a model, the underlying pretense has to be correct. Models deal with human data and if the inputs are junk so are the outputs. 

I understand why politically Streetsblog is trying to punch holes in TTI’s methodology. Streetsblog wants less money to be spent on roads and more money to be spent anywhere else. If Streetsblog can actually show that improving roads, specifically using managed lanes, does not improve travel, I will be the first to support a different approach. Unfortunately, this model appears more geared for political than transportation purposes.

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