August 1st, 2012
NEW METERSOptimize Mobility, by Catherine Higgins.
Ramp meters just put into service have helped I-15 traffic n Salt Lake County move more efficiently.
UDOT has recently put some ramp meters into service on northbound I-15 between 12300 South and 9000 South. The average speed during the p.m. commute is faster now that new ramp meters have been deployed.
“What we’re seeing so far at 8600 South is that the average speed went up 10 miles-per-hour,” says John Haigwood, Traffic Engineer at the Traffic Operations Center. Before the meters were turned on, motorists experienced backups on the ramps and sluggish traffic on mainline I-15. “Traffic is now free-flowing or freer flowing,” says Haigwood.
Ramp meters work to even out traffic on the freeway by breaking up bottlenecks and smoothing out speed surges. Meters also improve safety; stop-and-go driving behavior is reduced resulting in fewer rear-end collisions and platoons are broken up, resulting in fewer side-swipe collisions.
Research shows that the most significant benefit of using ramp meters is reliability which is the measure of the expected range of travel times allowing for crashes or excessive congestion. A Minnesota study showed a 91 percent decline in reliability when meters were turned off.
UDOT engineers continually evaluate ramp metering to make sure that commuters see a benefit.