Traffic-count Definitions

Fear of excessive traffic is a major fear expressed by those who oppose creating an I-75 Exit Ramp at Lincoln. The battle over the Lincoln Bridge continues, after almost two years of skirmishing involving residents, MDOT, the Royal Oak City Commission, the Oakland County Executive, an Oakland County Commissioner, and a State Representative.  Before that, there were traffic-count debates concerning Mohawk. Every time any change is considered, residents in the immediate area raise the excessive traffic argument.

Listening to those debates, one becomes aware that not everybody has the same understanding of frequently used traffic terms. From Mohawk resident Mary Ann Brown, I received a sheet which offers an excellent summary of street descriptions; the sheet's authenticity is confirmed by City Engineer Elden Danielson, who also supplied street names which typify each category. --- FJV: May 2006

Street Traffic Categories & Descriptions
Category Volume (ADT)* Street Traffic Description
Local Streets
 Royal . . .  Longfellow		 Low Range
0-600 ADT		 Generally carries only local, residential traffic on two lane gravel or paved surface. Peak hour traffic is estimated at one vehicle every minute.
Intermediate Range
600-1200 ADT		 Carries local and sub-collector traffic on two lane roadway and may provide access to activity centers on higher classified streets. Peak hour traffic is estimated at one vehicle every 30 seconds.
High Range
1200-1800 ADT		 Provides access to other local streets, activity centers on higher classified streets on two or three lane pavement. It may connect one collector  or arterial street to another similar street. Peak hour traffic is estimated at one vehicle every 20 seconds.
Collector Streets
 Normandy . . . Webster
Lincoln . . . Fourth Street		 Low Range
1800-2870 ADT		 Functions to carry traffic between local streets and major arterial streets or activity centers on two to four lanes. It is a principal traffic artery within residential areas and carries a higher volume of traffic than a local street. It may have minor retail or commercial establishments along its route. Peak hour traffic is estimated at one vehicle every 12 seconds.
Intermediate Range
2870-3940 ADT		 (Same description as low volume) Peak hour traffic is estimated at one vehicle every 9 seconds.
High Range
3940-5000 ADT		 (Same description as low volume) Peak hour traffic is estimated at one vehicle every 7 seconds.
Arterial
14 Mile . . . 13 Mile
11 Mile . . . Washington 		 5000+ ADT This major street in the hierarchy provides connections among county, state and interstate roads and is generally three to six lanes wide. It may have a significant number of community, retail, commercial and industrial facilities along its route. 
Freeway 
 I-75 . . . I-696		 100,000+ ADT

The highest traffic volume street in the highway system can vary in width from four lanes to as many as ten or more. Does not support direct access to residential or business property. Access to cross roads is generally at a minimum of one mile intervals.

*ADT = Average Daily Traffic