Tag Archives: Roadway

Sustainable Growth?

“Charlotte … perform(s) particularly bad. These systems do not have enough riders to produce the economies of scale that make transit provision by rail significantly less expensive than bus.” — UC Berkeley Urban Densities and Transit: A Multi-dimensional Perspective

While public transit is required to help accommodate the area’s population growth, the central question is what technology do we require to solve what problem? And when do you use one versus the other? So where rail transit might be economically sound by re-purposing along existing rail corridors surrounded by high-density populations, does it make sense to use rail transit all of the time? Is rail the only tool in the transit kit?

What really matters to transit-oriented development [TOD] outcomes?  According to the report, the #1 predictor is strong government support for redevelopment, while the #2 predictor is real estate market conditions.  The #3 predictor is the usefulness of the transit services — frequency, speed, and reliability as ensured by an exclusive right of way. Using rail vs bus technologies does not appear to matter much at all. — yes, great bus service can stimulate development!

There seems to be a continued LRT bias where advocates claim that LRT is the only way to support population growth using TOD (Transit Orient Developments) and that TOD has an inherent affinity for LRT over BRT. However, studies from the US GAO (BUS RAPID TRANSIT, Projects Improve Transit Service and Can Contribute to Economic Development) and a recent study of 21 North American transit corridors across 13 cities by the Institute for Transportation and Development Policy suggests otherwise. The study concluded that strong government support for redevelopment and real estate market conditions were the primary drivers that drove successful TOD. The use of transit technologies (rail vs bus) did not matter at all.

Outside of the US, in cities like Curitiba, Brazil, and Guangzhou, China, there is copious evidence that BRT systems have successfully stimulated development. Curitiba’s early silver-standard BRT corridors, completed in the 1970s, were developed together with a master plan that concentrated development along them. The population growth along the corridor rate was 98% between 1980 and 1985, compared to an average citywide population growth rate of only 9.5%.

Many cities, therefore, consider investing in mass transit to stimulate the hoped-for development. Indeed, a good mass transit investment can be such a catalyst. Yet city planners and politicians, who do not always work closely with transportation professionals, commonly begin to view mass transit in and of itself as a silver-bullet solution for stimulating development. — ITDP study, More Development For Your Transit Dollar

The DOLRT study area projects 32% population growth. It is the lowest projection of the counties and regions in the study, suggesting that there are other population areas that are growing substantially FASTER than the DOLRT corridor.

Based on the Alternative Analysis, the corridor study area is projected by 2035 to have a population density of 4052 ppsm or people per square mile (231K / 57). Using 1/2 mile walk-up radius around each of the 17 proposed stations, approximately 68,000 people will be within walking distance of a station. The national average for public transportation utilization is 5% (Durham 3%). This suggests walk access will be approximately 6800 daily boardings (68K * 5% * 2) rather than the projected 12,180 by GoTriangle in 2040.

dolrt_population_study

“It is broadly accepted that fairly dense urban development is an essential feature for a successful public transit system. Our analysis suggests that light-rail systems need around 30 people per gross acre … (for) cost-effective investments in the US … urban densities are the most critical factor in determining whether investments in guideway transit systems are cost effective” — UC Berkeley Urban Densities and Transit: A Multi-dimensional Perspective

So how much population density do we need to make light rail cost-effective?

dolrt_population_density

Let’s do the math, there are 640 acres in one square mile. So that means we would require a density of 19,200 people per square mile. So with our current 3071 ppsm (175K / 57) along the DOLRT study corridor, that is 16% of the recommended population density. Or stated differently, we would have to reach a population of over 1 million people by 2040 (or today’s entire Wake county population) just within the 57 square mile study corridor.

Reduced Congestion?

Unfortunately, the often promised traffic congestion relief has not been experienced by communities that implement LRT. You can look at two local examples (Charlotte & Los Angeles) or even in aggregate across the nation.

  • Charlotte LYNX daily ridership has stagnated at 16,000 over last 7 years, while the population grew 20%. Despite all this investment in LYNX, Charlotte was rated as the having the worse traffic in NC.
  • “L.A. Expo Line hasn’t reduced congestion as promised, a study finds.” article

In North Carolina, Eric Lamb, Manager of the City of Raleigh Office of Transportation, is not so sure about the correlation between transit and congestion abatement. He cites South Boulevard in Charlotte which directly parallels that city’s Lynx Blue Line light rail system. Despite the light rail line … there has been no corresponding reduction in traffic volumes along South Boulevard.

David Hartgen, emeritus professor of transportation studies at UNC Charlotte has authored a study concluding that the Triangle project would not reduce vehicle congestion or travel time, the very benefits supporters tout in seeking the outlay needed to fund the project.


“the presence of the rail line didn’t have a significant or consistent impact on the average speeds of motorists on the freeway and major, nearby surface streets.”L.A. Expo Line hasn’t reduced congestion as promised, a study finds


Generally, one-half or more of the light rail riders formerly rode bus services that were replaced by the rail service. The new ridership attracted to light rail from freeways is in fact quite small compared to the carrying capacity of a single freeway lane. The average freeway lane in US metropolitan areas that have built new light rail systems (since 1980) carries four times as many people per mile as light rail. Even signalized surface streets average twice as many people per mile as light rail. Breach of Faith: Light Rail and Smart Growth in Charlotte

Many advocates continue to claim that light rail reduces traffic congestion. However a closer look at the total national ridership statistics collected by APTA (1990 to 2014) reveals that total ridership over a 25 year period of massive investments in light rail development, the total ridership of local travel as represented by light rail and bus service has remained surprisingly flat at approximately 6 billion annual riders. Even with 28% US population growth, there is no evidence of increased ridership across these two modes of local public transportation. Evidence suggests that bus ridership has merely been shifted towards the more expensive light rail systems and has had no impact on reducing overall traffic congestion. Reference: Quarterly and Annual Totals by Mode – Collected by APTA

lrt_us

This passenger shift from bus transit to rail transit has also been experienced elsewhere. Researchers Shin Lee and Martyn Senior of Cardiff University (Do light rail services discourage car ownership and use? concluded thatGrowing rail shares in the light rail corridors have mainly come from buses and the evidence for light rail reducing car use is less clear. This latter finding is of particular significance, given that a major justification for investment in light rail rather than bus schemes is their presumed ability to bring about major modal shift by attracting substantial numbers of car users.

“There’s just the little problem of the evidence. With few exceptions, studies tend to find limited signs that transit has much of an impact on nearby road congestion. Some places see slight congestion gains or mileage declines in the short term, and well-designed service should lay the foundation for reduced car-reliance in the long run, but the direct transit-traffic link is tenuous at best.” Eric Jaffe, City Labs, Public Transit Does Not Have to Reduce Traffic Congestion to Succeed

So what happens if we don’t build the light rail project?

The mean travel time to work according to the 2014 US Census is 21.5 minutes (Durham County) and 22.0 minutes (Orange County). So what happens to travel times if we do not implement the DOLRT project? According to the DCHC MPO Alternatives Analysis, 2040 travel times using Existing+Committed is projected to be 27 minutes.

MPO_EC_travel_timesYet the proposed DOLRT will take 46 minutes (+10 minutes at terminus) . Now include the waiting time for the next train, the time to get to/from the station (via Park&Ride, Kiss&Ride, bicycle, walking, or bus transfer), it will even be LONGER. So how is this faster than the automobile that it is supposed to replace?

But it’s still more efficient than other alternatives?

The latest revised DOLRT optimistically projects 27,000 daily boardings (with NCCU extension in 2040) during 18.5 hours of daily operation across the 17.7-mile circuit (at a cost of $2.5 BILLION or $141 million per mile) to serve an average 730 passengers per hour (on each track). While advocates will argue that LRT has higher ‘capacity’, it will not necessarily mean that it has higher ‘usage.’ We should not confuse capacity with usage.

So how does that compare to the much hated highway? Well, not so well. A typical highways can accommodate 2,200 vehicles per lane per hour (human driven), utilizing about 5% of roadway capacity. And you can place 4 lanes within the same 50′ right-of-way required for DOLRT.

no_build_cap.jpg

And as autonomous vehicles become pervasive, this capacity will increase significantly, as the vehicles will be able to drive in much closer proximity thereby dramatically increasing the capacity of our existing roadway infrastructure. By using BRT, we will be able to organically add to this capacity; whereas with LRT relying on a roadway of steel rails, we will not, as it will be dedicated solely for the train and we will not be able to share with other autonomous vehicles.