Tag Archives: traffic

Idea of the Day: Bus Bunching

12 Jul
bus_bunching

Flickr photo by skew-t

If you’d come out of Buckhead Station’s north exit around 6:00 p.m. Tuesday you would have noticed two things: first, that there were far more people waiting for the route 110 bus than normal; second, that traffic was sitting absolutely still on Peachtree as far as you could see in both directions.
At 6:15, with the traffic creeping forward a few feet every few minutes and the bus scheduled to arrive at 6:13 nowhere in sight, you would have probably calculated that walking to the gym about a mile south of the station would be the quicker way to get there. But after walking south for about 10 minutes, around the time you were crossing Maple Drive, you would have noticed a route 110 bus heading north, toward the station you just left. You would have then noticed another one – directly behind the first. The first bus was very, very late. The second was almost on schedule.
What you would have seen is called bus bunching.
Bus bunching occurs when traffic or another delay slows down a bus’ progress along its route so much that the amount of the delay, as it’s compounded by the time required to stop and pick up passengers, exceeds the scheduled time between that bus and the one behind it. As the first bus continues along the route, it falls farther and farther behind schedule, as it has to keep stopping to pick up passengers. The second bus rarely has to stop, as there are very few or no passengers at all to pick up. Eventually the second bus is moving along the route so quickly that it catches up to the first one.  The shorter the headway, the more risk there is for bunching.
WABE and CNN recently posted stories about scientists at Georgia Tech who have developed an anti-bunching technique that relies less on schedules and more on calculated, adjustable delays coordinated by GPS. The system will be fully rolled out for the university’s Stinger Shuttle Tech Trolley system this fall and the developers say they’ve already been contacted by transit authorities here and abroad who are interested in implementing something similar.
Advertisements

Slow Going: Congestion stats from ARC

21 Feb

Image: ARC

The latest Atlanta Regional Commission’s “Regional Snapshot” shows how Atlanta’s traffic congestion stats stacks up against 14 other major metros. The ARC analyzed data from the American Community Survey, the American Transportation Research Institute and the Texas Transportation Institute and found Atlanta ranked:

  • 11th for total hours of congestion-related delays
  • 9th for the total number of jobs
  • 4th for the total number of hours that commuters spend traveling to their jobs each year. The Atlanta metro average was 126 hours per year, which equals about three weeks of workdays.
  • 4th for the percentage of workers who have at least a 45-minute commute to work
  • 1st in the Southeast for congestion cost per commuter. Here’s how the congestion cost was calculated

Metro Atlanta’s I-285 and 1-85 North interchange also ranked ninth among the 250 most congested bottlenecks in the country, according to American Transportation Research Institute data.

A possible upside to those numbers: “Areas with the most jobs tend to also have the most congestion,” the ARC report said. So, Atlanta’s status as a major job center is still intact, but that might soon be overshadowed by its reputation as a place to sit in traffic on the way to those jobs.

Vehicles 5, Fixed objects 1

6 Feb

This slideshow requires JavaScript.

A little enhancement to yesterday’s AJC story about the morning power outage in Midtown:

A few minutes before 9:30 a.m. there was a muffled explosion, quickly followed by another explosion, which was accompanied by a reddish-yellow flash of light. Believe it or not, I didn’t think much of it. It had been raining for two days. When I lived in Peachtree Hills, there was a transformer that could be relied upon to blow up in a shower of silver-blue sparks at least a couple of times whenever it rained for more than 24 hours.

But when I looked outside about 10 minutes later, the street was blocked by three police cars, a fire truck and an ambulance to the south. A large, black Chevrolet pickup truck with a utility pole right in the middle of its hood was straddling the curb to the north. There were also two small trees missing.

Continue reading

%d bloggers like this: