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Oklahoma DOT - Countermeasure Logic
Oklahoma DOT - Countermeasure Logic

This article summarizes the countermeasure logic used to determine addressable crashes associated with each Oklahoma DOT Countermeasure.

Greg Olsen avatar
Written by Greg Olsen
Updated over 2 months ago

The following Countermeasures are available as filters in AASHTOWare Safety, and will appear as recommended countermeasures in Safety Analysis. Each Countermeasure, its associated treatments, and the logic used to identify crashes associated with that countermeasure are documented below.

Roadside Design Improvements at Curves

Treatments

The following treatments are associated with the Roadside Design Improvement at Curves Countermeasure:

  • Widen Clear Zone from <= 2 m to >= 8 m (CMFID=3866)

  • Widen Clear Zone from (2 m, 4 m) to >= 8 m (CMFID=3867)

  • Widen Clear Zone from (4 m, 8 m) to >= 8 m (CMFID=3868)

  • Flatten sideslope from 1:3 to 1:4 (CMFID=28)

  • Flatten sideslope from 1:4 to 1:6 (CMFID=31)

  • Add 4 ft shoulder (Rural Multilane) (Zongzhi Table 7)

  • Add 4 ft shoulder (Rural Two-Lane) (Zongzhi Table 7)

  • Add 6 ft shoulder (Rural Multilane) (Zongzhi Table 7)

  • Add 6 ft shoulder (Rural Two-Lane) (Zongzhi Table 7)

  • Add 8 ft shoulder (Rural Multilane) (Zongzhi Table 7)

  • Add 8 ft shoulder (Rural Two-Lane) (Zongzhi Table 7)

  • Add 4 ft shoulder (Urban Multilane) (Zongzhi Table 7)

  • Add 4 ft shoulder (Urban Two-Lane) (Zongzhi Table 7)

  • Add 6 ft shoulder (Urban Multilane) (Zongzhi Table 7)

  • Add 6 ft shoulder (Urban Two-Lane) (Zongzhi Table 7)

  • Add 8 ft shoulder (Urban Multilane) (Zongzhi Table 7)

  • Add 8 ft shoulder (Urban Two-Lane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 6 ft (Rural Freeway) (6273/6279/6285)

  • Widen shoulder from 4 to 8 ft (Rural Freeway) (6291/6297/6303)

  • Widen shoulder from 6 to 8 ft (Rural Freeway) (6309/6315/6321)

  • Widen shoulder from 4 to 6 ft (Rural Multilane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 8 ft (Rural Multilane) (Zongzhi Table 7)

  • Widen shoulder from 6 to 8 ft (Rural Multilane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 6 ft (Rural Two-Lane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 8 ft (Rural Two-Lane) (Zongzhi Table 7)

  • Widen shoulder from 6 to 8 ft (Rural Two-Lane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 6 ft (Urban Freeway) (Zongzhi Table 7) (6276/6282/6288) (Zongzhi Table 7)

  • Widen shoulder from 4 to 8 ft (Urban Freeway) (Zongzhi Table 7) (6294/6300/6306) (Zongzhi Table 7)

  • Widen shoulder from 6 to 8 ft (Urban Freeway) (Zongzhi Table 7) (6312/6318/6324) (Zongzhi Table 7)

  • Widen shoulder from 4 to 6 ft (Urban Multilane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 8 ft (Urban Multilane) (Zongzhi Table 7)

  • Widen shoulder from 6 to 8 ft (Urban Multilane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 6 ft (Urban Two-Lane) (Zongzhi Table 7)

  • Widen shoulder from 4 to 8 ft (Urban Two-Lane) (Zongzhi Table 7)

  • Widen shoulder from 6 to 8 ft (Urban Two-Lane) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Freeway, 2 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Freeway, 4 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Freeway, 6 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Freeway, 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Freeway, > 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Multilane, 2 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Multilane, 4 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Multilane, 6 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Multilane, 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Multilane, > 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Two-Lane, 2 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Two-Lane, 4 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Two-Lane, 6 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Two-Lane, 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Rural Two-Lane, > 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Freeway, 2 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Freeway, 4 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Freeway, 6 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Freeway, 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Freeway, > 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Multilane, 2 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Multilane, 4 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Multilane, 6 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Multilane, 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Multilane, > 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Two-Lane, 2 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Two-Lane, 4 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Two-Lane, 6 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Two-Lane, 8 ft) (Zongzhi Table 7)

  • Pave deteriorated shoulders (Urban Two-Lane, > 8 ft) (Zongzhi Table 7)

  • Install roadside barrier (6402)

  • Improve guardrail (5551)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Roadside Design Improvement at Curves Countermeasure:

IF

Intersection-Related = False

AND

Road Alignment = Any of the following (Curve Left, Curve Right)

AND

Manner of Collision = Any of the following (Fixed object left of vehicle travel (including median), Fixed object right of roadway or unknown location, Pedestrian/cyclist right of roadway or crossing cross-street to the right of vehicle approach, Pedestrian/cyclist left of roadway or crossing cross-street to the Left of vehicle approach, Rollover or overturn not caused by collision with vehicle or identified fixed object)

Reduced Left-Turn Conflict Intersections

Treatments

The following treatments are associated with the Reduced Left-Turn Conflict Intersections Countermeasure:

  • Install J-Turn/RCUT (Edara section 4.1.2.4)

  • Install Median U-Turns (Hummer exhibit 4-4)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Reduced Left-Turn Conflict Intersections Countermeasure:

IF

Intersection-Related = True

AND

Manner of Collision = Any of the following (Both vehicles proceeding ahead at right angle to each other, Vehicle turning left with vehicle approaching from its left, Vehicle turning left with oncoming vehicle not turning, Vehicle turning left with oncoming vehicle turning right, Vehicle turning left with oncoming vehicle turning left, Vehicle turning left with vehicle approaching from its right)

AND

Traffic Signal = No Signal

Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Unsignalized)

Treatments

The following treatments are associated with the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Unsignalized) Countermeasure:

  • Systemic Intersection Treatments (urban, unsignalized) (Le Table 4)

  • Systemic Intersection Treatments (rural, unsignalized) (Le Table 4)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Unsignalized) Countermeasure:

IF

Intersection Related = True

AND

Traffic Signal = No Signal

Pedestrian-Centric Signal Modifications

Treatments

The following treatments are associated with the Pedestrian-Centric Signal Modifications Countermeasure:

  • Program leading pedestrian interval (Goughnour Table 40)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Pedestrian-Centric Signal Modifications Countermeasure:

IF

Intersection Related = True

AND

Traffic Signal ≠ No Signal

AND

Any Harmful Event = Pedestrian

Speed Management

Treatments

The following treatments are associated with the Speed Management Countermeasure:

  • Install 10 mph differential truck speed limit (rural freeways, truck-related crashes) [5329]

  • Install variable speed limit signs (urban freeways and principal arterials) (Avelar Table 9)

  • Set posted speed limit 5 mph below engineering recommendations (rural) (Gayah Table 12)

  • Set posted speed limit 10 mph below engineering recommendations (rural) (Gayah Table 12)

  • Set posted speed limit 15 mph below engineering recommendations (rural) (Gayah Table 12)

  • Implement mobile automated speed enforcement system at highly-enforced sites [2194]

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Speed Management Countermeasure:

IF

Unsafe / Unlawful = Any of the following (Unsafe Speed - Driver’s Ability (Aged), Unsafe Speed - Inexperienced Driver -, Unsafe Speed - For Traffic Conditions, Unsafe Seed - View Obstruction, Unsafe Speed - On Curve/Turn, Unsafe Speed - Other)

Enhanced Delineation and Friction for Horizontal Curves

Treatments

The following treatments are associated with the Enhanced Delineation and Friction for Horizontal Curves Countermeasure:

  • Improve curve delineation: delineators, markings, enhance retroreflectivity, add curve signs, best investment where RHR >= 5 (Srinivasan Table 7)

  • Improve curve delineation: delineators, markings, enhance retroreflectivity, add curve signs (dark environment), best investment where RHR >= 5 (Srinivasan Table 7)

  • Chip seal curve (freeway) (Merritt Table 24)

  • Chip seal curve (multilane) (Merritt Table 24)

  • Chip seal curve (multilane, wet road) (Merritt Table 24)

  • Chip seal curve (two-lane) (Merritt Table 24)

  • Chip seal curve (two-lane, wet road) (Merritt Table 24)

  • Diamond grind curve (freeway) (Merritt Table 25)

  • Diamond grind curve (freeway, wet road) (Merritt Table 25)

  • Thin HMA on curve (freeway) (Merritt Table 26)

  • Thin HMA on curve (freeway, wet road) (Merritt Table 26)

  • Thin HMA on curve (multilane) (Merritt Table 26)

  • Thin HMA on curve (multilane, wet road) (Merritt Table 26)

  • Thin HMA on curve (two-lane) (Merritt Table 26)

  • Thin HMA on curve (two-lane, wet road) (Merritt Table 26)

  • Open Grade Friction Course on curve (freeway) (Merritt Table 27)

  • Open Grade Friction Course on curve (freeway, wet road) (Merritt Table 27)

  • Open Grade Friction Course on curve (multilane) (Merritt Table 27)

  • Open Grade Friction Course on curve (multilane, wet road) (Merritt Table 27)

  • Open Grade Friction Course on curve (two-lane) (Merritt Table 27)

  • Open Grade Friction Course on curve (two-lane, wet road) (Merritt Table 27)

  • Groove pavement on curve (freeway) (Merritt Table 28)

  • Microsurfacing on curve (freeway) (Merritt Table 29)

  • Microsurfacing on curve (freeway, wet road) (Merritt Table 29)

  • Microsurfacing on curve (multilane) (Merritt Table 29)

  • Microsurfacing on curve (two-lane) (Merritt Table 29)

  • Microsurfacing on curve (two-lane, wet road) (Merritt Table 29)

  • Slurry seal curve (two-lane) (Merritt Table 30)

  • UTBWC on curve (freeway) (Merritt Table 31)

  • UTBWC on curve (freeway, wet road) (Merritt Table 31)

  • UTBWC on curve (two-lane) (Merritt Table 31)

  • UTBWC on curve (two-lane, wet road) (Merritt Table 31)

  • High friction surfacing on curve (Merritt Table 39) (Not EB)

  • High friction surfacing on curve (wet road) (Merritt Table 39) (Not EB)

  • High friction surfacing on curve (ramps) (Merritt Table 39) (Not EB)

  • High friction surfacing on curve (ramps, wet road) (Merritt Table 39) (Not EB)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Enhanced Delineation and Friction for Horizontal Curves Countermeasure:

IF

Intersection Related = False

AND

Road Alignment = Any of the following (Curve Left, Curve Right)

AND

Manner of Collision = Any of the following (Fixed object left of vehicle travel (including median), Fixed object left of vehicle travel (including median), Pedestrian/cyclist right of roadway or crossing cross-street to the right of vehicle approach, Pedestrian/cyclist left of roadway or crossing cross-street to the Left of vehicle approach, Rollover or overturn not caused by collision with vehicle or identified fixed object)

Backplates with Retroreflective Borders

Treatments

The following treatments are associated with the Backplates with Retroreflective Borders Countermeasure:

  • Backplates with Reflective Borders( CMF ID= 1410) 4Star

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Backplates with Retroreflective Borders Countermeasure:

IF

Intersection Related = True

AND

Traffic Signal ≠ No Signal

AND

Unsafe / Unlawful = Running Red Lights

AND

Traffic Control = Traffic Signal

Dedicated Left- and Right-Turn Lanes at Intersections

Treatments

The following treatments are associated with the Dedicated Left- and Right-Turn Lanes at Intersections Countermeasure:

  • Auxiliary Turn Lanes

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Dedicated Left- and Right-Turn Lanes at Intersections Countermeasure:

IF

Intersection-Related = True

AND

Traffic Signal ≠ No Signal

AND

Manner of Collisions = Rear End, Stopped; Rear End, Motion; Rear End, Turning Left; Rear End Turning Right; Right Angle Straight

Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Night, Unsignalized)

Treatments

The following treatments are associated with the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Night, Unsignalized) Countermeasure:

  • Systemic Intersection Treatments (rural, night, unsignalized) (Le Table 4)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Night, Unsignalized) Countermeasure:

IF

Intersection-Related = True

AND

Traffic Signal = No Signal

AND

Light Conditions = Any of the following (Dark / Unlighted, Dark / Lighted, Dawn, Dusk, Dark / Unknown Lighting)

Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Signalized)

Treatments

The following treatments are associated with the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Signalized) Countermeasure:

  • Systemic Intersection Treatments (urban, signalized) (Le Table 4)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Signalized) Countermeasure:

IF

Intersection-Related = True

AND

Traffic Signal = Incandescent Flashing Beacon on Mast Arm, Incandescent Flashing Beacon on Pedestal Pole, Incandescent Flashing Beacon on Span Wire

Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Night, Signalized)

Treatments

The following treatments are associated with the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Night, Signalized) Countermeasure:

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Systemic Application of Multiple Low-Cost Countermeasures at Stop-Controlled Intersections (Night, Signalized) Countermeasure:

IF

Intersection-Related = True

AND

Traffic Signal = Incandescent Flashing Beacon on Mast Arm, Incandescent Flashing Beacon on Pedestal Pole, Incandescent Flashing Beacon on Span Wire

AND

Light Conditions = Any of the following (Dark / Unlighted, Dark / Lighted, Dawn, Dusk, Dark / Unknown Lighting)

Centerline Rumble Strips

Treatments

The following treatments are associated with the Centerline Rumble Strips Countermeasure:

  • Add centerline rumble strips (urban, two-lane) (NCHRP 641 Table 67)

  • Add centerline rumble strips (rural, two-lane) (NCHRP 641 Table 67)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Centerline Rumble Strips Countermeasure:

IF

Intersection-Related = False

AND

Manner of Collision = Any of the following (Vehicles proceeding ahead in opposing directions, sideswipe, Vehicles proceeding ahead in opposing directions, head-on)

AND

Unsafe / Unlawful = Left of Center - In Meeting

Edgeline Rumble Strips

Treatments

The following treatments are associated with the Edgeline Rumble Strips Countermeasure:

  • Add edgeline rumble strips (urban freeways) (NCHRP 641 Table 26)

  • Add edgeline rumble strips (rural two-lane) (NCHRP 641 Table 28)

Countermeasure Logic

The following logic is used to determine if crashes would be potentially mitigated by the Edgeline Rumble Strips Countermeasure:

IF

Intersection Related = False

AND

Manner of Collision = Any of the following (Fixed object left of vehicle travel (including median), Pedestrian/cyclist in roadway, near side of intersection or unspecified, Pedestrian/cyclist right of roadway or crossing cross-street to the right of vehicle approach, Pedestrian/cyclist left of roadway or crossing cross-street to the Left of vehicle approach, Rollover or overturn not caused by collision with vehicle or identified fixed object)

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