Oregon Bulletin

November 1, 2012

Department of Transportation, Highway Division, Chapter 734

Rule Caption: Locations and Criteria of Variable Interstate Speed Limits.

Adm. Order No.: HWD 10-2012

Filed with Sec. of State: 9-27-2012

Certified to be Effective: 9-27-12

Notice Publication Date: 8-1-2012

Rules Amended: 734-020-0019

Subject: ORS 810.180 authorizes the Department of Transportation to conduct speed zone investigations and set speeds on most public roads, including interstate highways. As amended, 734-020-0019 will not show any current locations of variable speed limits on the Interstates because ODOT has decided that advisory speeds are sufficient for previously listed locations.

Rules Coordinator: Lauri Kunze—(503) 986-3171


Locations and Criteria of Variable Interstate Speed Limits

(1) All locations of mainline interstate highways have speed limits set in OAR 734-020-0011 or a maximum speed limit of 65 MPH per ORS 811.111(1)(a). The speed limit for vehicles listed in 811.111(1)(b) is 55 mph unless a lower speed is posted under section (3) of this rule or in section (2) of OAR 734-020-0011.

(2) There are no variable speed limit locations on the interstate at this time.

(3) Criteria for Changing Speeds.

(a) Normal automated variable speed limits:

(A) The minimum traffic volume for variable speed limit system operation shall be greater than 1,200 vehicles per hour in any lane.

(B) Speed limits between subsequent highway sections shall not be reduced by more than 10 MPH.

(C) The speed limit shall be lowered in 5 MPH increments.

(D) The speed limit shall not be changed more than once within a 5 minute period.

(E) The minimum variable speed limit shall not be less than 30 MPH.

(F) The variable posted speed limit shall be within 10 MPH below the 85th percentile speed and posted in accordance with the following Table:


85TH percentile speed (MPH) — Posted Speed (MPH)

55 — 50

50–54 — 45

40–49 — 40

30–39 — 35

Less than 30 — 30

(b) During periods of crashes and other traffic lane blockage incidents the Transportation Operations Center may establish variable speed limits other than the normal automated variable speed limits in accordance with the following:

(A) The speed increment of 5 MPH for changing the speed under normal conditions may be system overridden.

(B) The minimum traffic volume criteria may be system overridden.

(C) The minimum 5 minute period for changing speeds may be system overridden and the posted speed changed immediately to the minimum of 30 MPH.

[ED. NOTE: Tables referenced are available from the agency.]

Stat. Auth.: ORS 184.616, 184.619, 810.180 & 811.111
Stats. Implemented: ORS 810.180 & 811.111
Hist.: HWD 1-2012, f. & cert. ef. 1-27-12; HWD 10-2012, f. & cert. ef. 9-27-12

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