The Arizona Department of Transportation said speed limits along parts of Grand Avenue (US 60) in the Northwest Valley have changed.

For safety reasons, ADOT waited until the completion of recent construction projects before evaluating traffic speeds and other factors and determining that the Grand Avenue speed limits between Thunderbird Road in El Mirage and R.H. Johnson Boulevard in Surprise will be raised, a release states.

The speed limit along Grand Avenue between Thunderbird Road and Reems Road has been raised from 45 mph to 50 mph. That 50 mph limit also extends in the westbound direction for half a mile west of Reems Road.

The speed limit along the rest of the section of Grand Avenue between Reems Road and R.H. Johnson Boulevard has been raised from 45 to 55 mph. Speed limit signs were changed Thursday morning.

The speed limit changes are based on safety considerations, according to ADOT. The updated speed limits are designed to reduce differences, or variations, in vehicle speeds along the sections of Grand Avenue west of Thunderbird Road. According to traffic engineers, the safest conditions occur when most traffic is traveling at nearly the same speed.

Earlier this year, ADOT completed roadway and intersection improvements between Thunderbird and Greenway roads. The agency also made major safety and traffic improvements by building the Bell Road bridge that now carries traffic over Grand Avenue and the BNSF Railway tracks in Surprise.