Why is it for drivers traveling north on Riverside Avenue between Barnett Road and the downtown area, the speed limit is 30 mph, but when traveling south on Central Avenue in the same area the speed limit is 35 mph? My son thinks it may be the motels on the Riverside side that may cause the slow-down.

Why is it for drivers traveling north on Riverside Avenue between Barnett Road and the downtown area, the speed limit is 30 mph, but when traveling south on Central Avenue in the same area the speed limit is 35 mph? My son thinks it may be the motels on the Riverside side that may cause the slow-down.

— Frank A., Phoenix

We at Since You Asked Headquarters' Traffic Division were glad to see your question, Frank, because we have wondered the exact same thing. Although more troubling to us is why drivers heading north out of Phoenix on Highway 99 drive about 30 mph for a mile despite the speed limit there being 45 mph, but that's a whole other SYA.

According to Alex Georgevitch, city transportation manager, and Ralph Browning, city engineering technician, one difference between the two streets is the on-street parking along Riverside in that section while there is none on Central south of 10th Street.

Browning said the speed limit on Central Avenue south of 10th Street used to be 25, then a couple of years ago citizen requests led to a study, review and increase to 35. At 10th Street, Central shifts from two lanes to three lanes, and it's outside of the downtown area.

Georgevitch said the state speed control board must approve speed limit changes, and changes are driven by requests from the public, unless there are safety issues. Riverside's speed limit has been 30 mph for a long time, and no one has requested a speed limit change for that street, said Browning.

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