Big challenges, big rewards using highway shoulder Published: Sunday, March 29, 2015
Public works officials and engineers mulling the possibility of allowing drivers to use the shoulder on the Churchill-Roosevelt Highway for rush-hour travel will have to weigh the potential benefits of such a measure with sizeable costs and logistic challenges.
The idea was publicised earlier this month by Works and Infrastructure Minister Suruj Rambachan, who laid out a series of proposals for alleviating traffic along Trinidad’s roadways in an interview with the Sunday Guardian. One of those ideas: using the shoulder of the highway as an extra travel lane that would operate daily during the hours of highest congestion, a traffic release valve that could bring about quicker commutes and happier drivers.
It’s a tempting prospect: the construction expenses of adding a permanent lane or two on a highway are astronomical, typically costing taxpayers $10 million to $50 million per mile.
Using a shoulder or breakdown lane costs comparatively little. It’s a bang-for-your-buck quick fix that would likely allow traffic to flow more quickly, at least in the short term.
But conclusions from similar traffic experiments conducted in major metropolitan areas around the globe suggest that successful execution of the idea will require careful planning and substantial capital investment.
Former highway director Roger Ganesh, who planned for the completion of a feasibility study before his retirement last December, said the project would need technologically sophisticated signs that could display real-time commands to motorists on whether the lane was open or closed, as well as the construction of new “refuge areas” along the highway to provide vehicles with the space to pull over in case of an emergency.
“This is something that has been going on for a number of years in the States and Europe and the UK,” Ganesh said. “It has to be well-signed and controlled...You’re not just opening up the shoulders, but you have to go with the infrastructure changes to manage it properly.”
Ganesh said the highway department had hired the consulting firm IBI Group to conduct a feasibility study on the proposal’s potential rewards and drawbacks that he expected to conclude by the end of the summer. A representative of IBI Group declined to respond to a request for information on the preliminary findings of their study.
In the past 30 years, cities in Europe and the United States have introduced similar strategies. In one instance in Great Britain, peak-period use of the shoulder of the road reduced travel times by as much as 24 per cent, and increased capacity on the roads by an average of seven to nine per cent. Preliminary studies suggested that the measure also decreased car crashes and reduced vehicle emissions. But their system also requires regular maintenance and round-the-clock monitoring of thousands of roadside surveillance cameras and traffic sensors.
Ganesh suggested that the stretches of highway that could best benefit from the breakdown lane experiment could be the stretch of Churchill-Roosevelt Highway from Port-of-Spain to Golden Grove Road, and Uriah Butler Highway from its northern terminus to the Couva off-ramp. Ganesh also recommended that the lane only be available to small passenger vehicles—no trucks, maxis or buses that would place extra wear and tear on the shoulders of the road.
Additionally, following in the footsteps of other cities, Trinidad’s lane management system would require overhead highway signs with electronic displays that would inform drivers when the extra lane was open or closed: during rush hour, the sign would show a large green arrow, and during off-peak hours it would present a red “X.”
This strategy could address one of the biggest problems with part-time use of the shoulder of the road: safety. Breakdown lanes allow emergency vehicles to bypass bumper-to-bumper traffic and offer protection for vehicles that break down in the middle of traffic or drivers experiencing an emergency.
With the use of electronic signs, Ganesh said, highway managers who spot a stalled vehicle, a serious collision, or an approaching ambulance can quickly alert drivers when they suddenly need to leave the breakdown lane, even in the middle of rush hour.
In other places, highway authorities have also installed emergency refuge areas at regular intervals along the highway, where people can pull over at last resort.
“It’s still cheaper to do this than to construct a full lane,” Ganesh said. “Economically, it’s very viable.”
Opening a highway shoulder to traffic would also likely incur other costs. Law enforcement officials would be needed to enforce the new rules. Public works officials would need to repaint lane markings and move some of the existing highway signs, signposts, and guard rails further away from the shoulder of the road. And, according to the US Federal Highway Administration, the introduction of peak-time travel in the breakdown lane often leads to an increase in the number of collisions between cars and signs, barriers, drains, and streetlights. The repair costs add up.
Some engineers are critical of this strategy. Their theory—known by the adage “If you build it, they will come”—is that widening roads doesn’t do much to help eliminate traffic in the long term. If you build more capacity for vehicles on the highway, you will ultimately just increase the demand for road space and number of cars vying to use the highway during rush hour.
How it worksHere’s how it works: once a new lane opens up and people notice how much more quickly traffic moves along the highway, they decide that they want to drive on the unclogged highway, too. In some cases, people who otherwise use PTSC buses or maxi taxis for their daily commute will instead choose to drive. In other cases, people who had previously arranged their schedule to intentionally avoid peak-time traffic (for example, leaving for work before 5.30 am or after 9 am) may begin to travel during peak-time hours because they know that traffic might not be as painfully slow as before.
Roy Kienitz, a transit engineer who formerly worked for the US Department of Transportation, is widely known for explaining the folly of widening highways with this colourful metaphor: “Widening roads to ease congestion is like trying to cure obesity by loosening your belt.”
With this phenomenon in mind, some other cities in Canada, the US, Ireland, and New Zealand have decided to use that space on the shoulder of the road to create a rush-hour lane exclusively for public transit, which helps to provide better, faster bus service and decreases the number of cars driving along the highway.
But Ganesh said this option may not be a possibility for Trinidad. The structural design of the shoulder of the road would not be able to accommodate the weight of buses travelling regularly along the route. And allowing private passenger vehicles to travel on the breakdown lane would still have environmental benefits: faster travel times would reduce greenhouse emissions from cars that currently spend hours each week idling in bumper-to-bumper traffic.
http://www.guardian.co.tt/lifestyle/201 ... y-shoulder
Think he meant officially.
