Ramp Meters

Phoenix-area drivers are used to seeing freeway entrance-ramp meters with alternating green and red traffic lights during weekday rush hours. But some of the red lights in Interstate 17 ramp meters also play a role as part of the pilot wrong-way vehicle detection system being tested by the Arizona Department of Transportation.

PHOENIX – Starting this week, the timing of ramp-meter signals along southbound State Route 51 (Piestewa Freeway) are being adjusted to respond to the flow of morning rush-hour traffic, expanding an Arizona Department of Transportation program that began last fall along the freeway’s northbound on-ramps.

PHOENIX – One of the benefits of the recent widening of Loop 101 in the Scottsdale area is that on-ramp meters, featuring those alternating green and red traffic signals, won’t be in use as often now.

PHOENIX – With a goal of improving the rush-hour traffic flow, the Arizona Department of Transportation will test changes in the timing of ramp-meter signals along one Phoenix-area freeway.

Starting the week of Oct. 3, afternoon rush-hour drivers using on-ramps along northbound State Route 51 (Piestewa Freeway) are likely to notice longer red lights at ramp meters as ADOT takes a look at how the signal adjustments affect freeway traffic.

Ramp meters help to control the flow of traffic entering a freeway.

Much has changed since ADOT got its start in 1927. Back then, the agency was known as the Arizona State Highway Department and roads certainly were built a little differently. Methods, materials and technology have changed so much since then.

If you drive Valley freeways during rush hour, you’re probably pretty familiar with ramp meters … They’re the two-light signals positioned at most Valley on-ramps that tell motorists when it’s okay to head onto the freeway. Ramp meters have been used in the Phoenix-Metro area for about the past 20 years and maybe you think not much about them has changed … but, actually they’ve recently become much more efficient!