The Miracle of Flex Lanes

By Cindy M. Huss posted 04-16-2018 15:04

​It is estimated that over 60,000 vehicles travel US 23 between Ann Arbor and Brighton during rush hour. Traffic congestion and delays were normal in years past. In November 2017, after one torturous year of construction, the new flex lane system opened between M-14 and M-36 on US 23 to the north of Ann Arbor. It is the first of its kind in Michigan and it is amazing. The time for my eight-mile commute to ICLE has shortened dramatically. What used to take 35 to 40 minutes now takes 15 to 20 minutes.

The typical solution for traffic congestion, adding additional lanes, is not always an option. Flex lanes have been used for years on city streets where widening the road was not feasible. City streets in Salt Lake City and Cleveland use red crosses and green arrows over the lanes to designate when you can use them. These systems were found to be a safe and effective way to decrease congestion and improve the flow of traffic during rush hours. In Washington, DC, and on the Golden Gate Bridge, they use moveable barrier machines to actually move the center barrier to increase the number of lanes going into the city in the morning and out of the city in the evening. The cost of these machine barrier systems is obviously high.

When US 23 was constructed in 1926, it cut through several already well-developed lake communities north of Ann Arbor. As a result, many houses, businesses, and roads abut right up to the US 23 boundary fence. Widening from two to three lanes on each side would presumably have required a significant amount of condemnation. The state decided a 24-hour fix through additional lanes was not needed to address periodic traffic problems. A flex lane system could be used only when needed and could be done within the existing footprint of the roadway. For US 23, overpasses that were in poor shape to begin with had to be torn down and rebuilt to make room for the flex lanes. Otherwise, by using the center median and the shoulders, no further expansion was required. The estimated savings for constructing flex lanes as opposed to actual additional lanes was $308 million.

Green arrows and red crosses appear above the flex lane, along with message boards that tell you when you can use the flex lane. When I get on US 23 now, I know it will be smooth sailing when I see that green arrow. Sometimes, when I work late, it makes me sad to see a red cross over the flex lane. Not because the traffic is heavy or slow but just because the flex lane makes me happy. Hopefully you will be able to experience the joy of the green arrow when you are next visiting Ann Arbor during a high-traffic period. Watch for it on art fair days, or football game days, or even when you are coming to be a contributor in the ICLE studio. (By the way, that 60 mph sign by the green arrow is technically only a suggested speed.)