i-664 eastbound on-ramp at bridge rd study

8/9/2019 I-664 Eastbound on-ramp at Bridge Rd Study

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April, 2014

HSIP Road Safety Assessments:

Bridge Road

I-664 Eastbound on Ramp

Suffolk, Virginia

Prepared for:

City of Suffolk- Traffic Engineering

Prepared by:Robert M Greenwood

2014.04.16 13:01:01 -04


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City Of Suffolk: HSIP Bridge Road I-664 EASTBOUND ON RAMP 2

TABLE OF CONTENTS

1.0 INTRODUCTION ........................................................................................................................3

2.0 STUDY AREA AND METHODOLOGY ...........................................................................................4

3.0 EXISTING CONDITIONS/ OBSERVATIONS ...................................................................................4

3.1 GEOMETRIC CONDITIONS ......................................................................................... 7

3.2 TRAFFIC CONTROL DEVICES ...................................................................................... 9

3.3 TRAFFIC CONDITIONS................................................................................................ 9

3.4 CRASH ANALYSIS ....................................................................................................... 9

4.0 ROADWAY SAFETY ASSESSMENT ............................................................................................ 11

4.1 SAFETY ISSUES AND CONTRIBUTING FACTORS ...................................................... 11

4.2 RECOMMENDED IMPROVEMENTS ......................................................................... 14

APPENDIX

APPENDIX A: Crash Diagram


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Photograph 1:Westbound Approach to the On-Ramp on Bridge Road

Photograph 2:Eastbound Approach to the On-Ramp on Bridge Road


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Photograph 3:Southbound view of the On-Ramp

Photograph 4:Eastbound view of the On-Ramp


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3.1 GEOMETRIC CONDITIONS

The intersection of Bridge Road and I-664 Eastbound on-ramp is an un-signalized intersectionwithin the City of Suffolk. Bridge Road is a four lane divided roadway. The I-664 Eastboundon-ramp is a single lane ramp. Eastbound Bridge Road has access to the on-ramp from a curvedslip lane that merges onto the ramp under yield control. Westbound Bridge Road has access to

the on-ramp by executing a left turn from a median break on Bridge Road. There is a left turnstorage lane at the median opening.

Bridge Road at this intersection is horizontally straight. There are no vertical curves through theintersection. Four-foot paved shoulders are provided for Bridge Road eastbound only, prior tothe intersection. Bridge Road eastbound and westbound (after the intersection) has softshoulders. The I-664 eastbound on-ramp has standard paved shoulders on both sides of theramp. The slip ramp alignment follows a small radius.

Lane use at the intersection consists of the following:

Bridge Rd. eastbound: 2 through lanes, and 1 right-turn slip lane

Bridge Rd. westbound: 1 left-turn lane, and 2 through lanes

No pedestrian accommodations are currently present at this intersection.


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City Of Suffolk: HSIP Bridge Road I-664 EASTBOUND ON RAMP

Table 1: Crash Summary

Year

Peak Light Condition Pavement Condition Type of Collision SeverityTOTAL

by YearAM

(6-10)

PM

(3-7)

Off

PeakDay

Dawn/

DuskDark Dry Wet Misc

Rear

EndAngle

Sideswipe-

same dir.Animal Fatal Injury

Property

Damage

2011 3 2 1 4 5 5 1 4 5

2012 2 1 3 3 1 2 6 1 3 1 1 1 1 4 6

2013 1 2 1 1 1 1 2 1 1 1 3 3

TOTAL 3 4 7 4 3 7 12 2 0 2 9 2 1 1 2 11 14

14%

64%

14%

7%

% Type of Collision

Rear End

Angle

Sideswipe- same dir.

Animal


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4 0 ROADWAY SAFETY ASSESSMENT

4.1 SAFETY ISSUES AND CONTRIBUTING FACTORS

The following is a summary of observed intersection issues and factors that may potentially

contribute to vehicle crashes at this location or have the possibility of creating a safety concernalong Bridge Road in Suffolk Virginia.

Pavement in the vicinity of this intersection is

showing signs of deterioration. Pavement at the

entrance to the on-ramp (Picture 4-1) and

pavement in the middle of the intersection is

showing signs of wear.

There is considerable shoulder erosion in the

vicinity of the intersection. The right shoulder on

the westbound side of Bridge Road (Picture 4-2)

has a 3 drop off.

Picture 4- 2

Picture 4- 1


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The median crossover at the I-664 on-ramp has an algebraic grade differential of 11.8%

over 8 to 10 feet. The truck with trailer (Picture 4-3) and the passenger vehicle (Picture

4-4) provide a visual illustration of the grade differential in the median crossover.

The right turn slip ramp from eastbound Bridge Road onto the I-664 on-ramp is

controlled by a single Yield sign posted on the right hand side of the ramp. The Yield

sign is occluded by a stand of trees as the motorist enters the slip lane and only

becomes visible at 300-feet from the sign. Picture 4-5 was taken when the trees did not

have foliage. The posted advisory speed for the slip ramp is 25 mph. There are no

Yield Ahead sign for this approach. Figure 3 depicts a plan view of the roadway

geometry of the intersection and illustrates the Yieldsign occlusion.

Picture 4- 3 Picture 4- 4

Picture 4- 5

Yield Sign


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The interchange lighting at I-664 and Bridge Road was removed by or before November

2011. This intersection is unlighted in the evenings and with the slip ramp located 530-

feet from the median crossover, a left turning vehicle may have difficulty determining

whether an eastbound vehicle on Bridge Road is exiting via the slip lane or continuingeastbound on Bridge Road towards the intersection.

Bridge Road has a posted speed limit of 45 mph. A speed study was performed by the

City for the eastbound direction of Bridge Road. The speed study revealed an 85th

percentile speed of 57 mph. The eastbound slip ramp point of divergence is located 530-

feet from the median opening for left turns from westbound Bridge Road onto the I-664

on-ramp. According to the VDOT Road Design Manual - Appendix G: Access

Management Design Standards for Entrances and Intersections, the intersection sight

distance for a 45 mph roadway needs to be at least 580-feet. The intersection sight

distance for a 55 mph roadway needs to be at least 710-feet. The current sight distancefrom the median opening exceed 710-feet. However, as noted in one crash report, the

driver making the left turn from the median opening reported that they presumed that

the eastbound Bridge Road vehicle was exiting onto the I-664 slip ramp and could not

complete the left turn movement and the eastbound vehicle could not stop prior to the

crash. Figure 3 depicts a plan view of the roadway geometry of the existing intersection

and illustrates the non-complaint intersection sight distance for making a left turn

movement.

Figure 3


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4.2 RECOMMENDED IMPROVEMENTS

The following is a summary of the suggestions to improve safety and potentially reduce thenumber and severity of accidents at this location. As mentioned in the introduction, suggestionsfor safety improvements have been categorized into short, intermediate, and long termrecommendations.

Short Term

Conduct shoulder restoration along the ramp to I-664 and along the southbound side ofBridge Road.

Repave intersection to improve pavement quality.

Install a second Yield sign to the left of the approach on the eastbound I-664 slip rampwith Yield line pavement markings. The second Yield sign will not be occluded by thetree branches.

Install Yield Ahead signs on the eastbound I-664 slip ramp.

Intermediate

Provide roadway lighting along Bridge Road from the west side of the I-664 overpass,westbound approximately 1100-feet. (Budgetary estimate for PE - $ 20,000;Construction $ 80,000)

Reconstruct the median crossover to remove the 11.8% crossover grade. (Budgetaryestimate for PE - $30,000; Construction $ 135,000)

Stormwater requirements for this recommended work are not clearly definedand may impact the budgetary estimate.

Long Term

Reconstruct the eastbound slip lane on-ramp to accommodate a design speed of 55mph. The reconstruction envisioned is to extend the exit location on Bridge Roadapproximately 200-feet west of its current location.


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APPENDIX


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APPENDIX A: Crash Diagram


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i-664 eastbound on-ramp at bridge rd study

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