Following an independent study and public input, the Arizona Department of Transportation is raising the Interstate 17 speed limit south of Peoria Avenue to 65 mph.
The new speed limit will take effect when ADOT replaces the current 55 mph signs along I-17 between the I-10 “Split” interchange and Peoria Avenue, which is expected to be done by the end of October.
The study determined a 65 mph speed limit within that stretch of I-17 is appropriate since it more closely reflects the speed most people are currently driving and find reasonable. This is likely to improve compliance, providing an effective tool for law enforcement.
The evaluation also notes a 65 mph speed limit can result in more drivers traveling closer to the same speed, which enhances safety.
The study ADOT commissioned followed passage of legislation (SB 1102) that calls for a minimum speed limit of 65 mph on any interstate highway in counties with a population of 3 million or more people. The law stipulates that a lower speed limit can be set if certain conditions are met, including:
- A lower limit is deemed necessary based on an independent engineering study or roadway assessment.
- The overall system capacity and mobility along the freeway will not be reduced.
- An opportunity for public input is provided.
The speed limit is at least 65 mph on all other stretches of interstate highways in the Phoenix area. Maricopa County is Arizona’s only county with a population topping 3 million.
Nearly 11,000 people submitted feedback to ADOT in a public survey. Approximately 75 percent of respondents supported raising the speed limit to 65 mph.
Arizona law allows ADOT to establish speed limits on the state highway system “upon the basis of an engineering and traffic investigation.” The I-17 speed study evaluated a wide variety of factors including the average speeds that motorists are traveling, crash history, traffic volumes and the roadway design, to recommend an appropriate speed limit.
