Higher speed limits on parts of I-294, I-88 and I-355 were recommended for approval Thursday by the Illinois Tollway’s customer service and planning committee.
According to the state’s vehicle code, the tollway is required to conduct an engineering and traffic investigation before raising its maximum speed limits.
The investigation — which took factors like prevailing speed, high-crash segments, access point density and the volume of traffic congestion into consideration — determined that the 70 mph maximum that is allowed by the state is not a “safe and reasonable increase in the speed limit” for certain sections of the highway…
Once all the necessary approvals are complete the Illinois Secretary of State can publish the updated rules and the new speed limit signs can be installed. Tollway officials estimate that the new speed limit signs could be posted this summer.
It sounds like safety concerns led to this slight increase. But, I would be interesting in seeing this study as the reasoning behind a slight increase is not clear. If prevailing speed is a factor, we know that a good number of Chicago-area highway drivers still go faster than the new 60 or 65 mph speed limits. How many more crashes and deaths will occur with a 60 or 65 mph speed limit? Does this mean Illinois is not joining the move toward zero-death roads? And if there is more damage, how is the positive side calculated (less time lost, less congestion, etc.)? At the same time, raising the speed limits won’t necessarily lead to faster driving; evidence from Michigan suggests people will continue to drive at the speed at which they feel comfortable.