Why are trains usually more reliable than buses? Mostly because they don’t have to mix with other vehicles. Dedicated rights-of-way—in this case, tracks—help trains move quickly and evenly; they’re not constantly dragged down by car traffic like their rubber-tired counterparts. (Unless it’s a streetcar, a topic for another day.)
But buses can run fast, too, when they’re given a fair shot. The democratizing force is a dedicated lane, which can allow buses to carry upwards of four times as many travelers per hour than a general traffic lane. Separate lanes can also double or triple bus speeds by eliminating delays caused by single-occupancy vehicles. (Just look at what Seattle has done with a few dedicated lanes downtown.)
Not every street that could benefit from a bus lane could fit one, sadly. On streets with only a single lane available in each direction, bus riders have been generally doomed to suffer. But that doesn’t have to be the case, according to Vikash Gayah and S. Ilgin Guler, two professors of civil and environmental engineering at the Pennsylvania State University, if a “pre-signal” is in the mix.
Traffic signals that give buses priority at the intersection aren’t uncommon on arteries with dedicated bus lanes. Pre-signals, on the other hand, are a very rare bird of traffic planning: These traffic lights are placed mid-block—“upstream” from regular signalized intersections, as the engineers like to say—and actively change the flow of traffic before vehicles hit the intersection at all. This helps avoid conflict and delays amid crosscurrents. In the real world, pre-signals are only known only to exist on few multilane roads in the U.K. and Switzerland. But Gayah and Guler recently developed and simulated a strategy that would allow two-lane, two-way streets to get on board, and essentially create a dedicated bus lane out of thin air.
Click here to read the full article: https://www.citylab.com/transportation/2018/05/dedicated-bus-lanes-without-the-extra-lane/561509/