Tyregrip Safety System

Tony Becker – Ennis Traffic Safety Solutions

Ennis Product Line

Focused on Highway Safety

•Traffic Striping & Marking Paint•Thermoplastic•Raised Pavement Markers•Plural Component Durables

•Epoxy, MMA, Modified UrethanesSkid Resistant Pavement Treatments

Provide Skid Resistant Pavement Surfaces

• Curves may justify a higher threshold value for a friction-related parameter.

• Higher speed facilities may justify a higher threshold value for a friction-related parameter.

• An increased probability of wet-weather conditions would justify a higher level of texture or higher

threshold value for a friction-related parameter.

Tyregrip safety system

Applications•Horizontal curves

•Intersections

•Steep grades

•Delaminated bridge decks

Tyregrip

Brief History

• Development was a joint effort between Prismo Safety Corporation and the British government.• Tyregrip was first conceived in 1967 as a means to reduce skidding at junctions in London, England.• Non-skid treatments are mandated throughout England and Europe to reduce skidding and crashes at junctions and horizontal curves.

What is Tyregrip?

Tyregrip is a high friction system designed to increase highway safety.

• The first part of the system is a two component exothermic epoxy resin base binder.• The second part is a course aggregate comprised of Bauxite, crushed in angular shapes to provide the friction• They are applied either manually or by equipment as a system to provide minimum friction coefficient numbers in the 70s.

The science of Tyregrip

• Friction is based on surface area of tires and touch points.Grooved pavements reduce surface area in contact with tires.

• At first grooved pavements maintain good levels of friction; eventually the pavement polishes and the coefficient of friction drops.

• By maintaining as much tire as possible with the roadway friction is increased and skidding prevented.• Little noticeable difference in decibel sound measurements depending on pavement types.

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Horizontal Curves and Safety

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Cra

sh

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/km

Tangent Segments

Curves and Transitions

Average crash

rates for

horizontal curves

is about 3 times

that of tangent

segments

Source: Glennon, et al, 1985 study for FHWA

2008 Horizontal Curve Fatal Crashes

28% Straight

Curve72%

Speeds on Curves

Driver Behavior Vs. Model Assumptions

Horizontal Curves

Project Examples

Arizona DOT

HFS Installation – April 2008

Arizona DOT Safety Trial

• Crashes into barriers on sharp curve• Product evaluation trial

• Mike Manthey, State Traffic Engineer• Assistance provided by AZ DOT maintenance dept, Phoenix• Contractor – Pavement Markings Inc. of Arizona

Arizona DOT

Hwy 60 West to Hwy 101 South Loop Interchange

Arizona Hwy 60 W to Hwy 101 S

Treated Area Shown in Yellow

Problem Statement

•The local fire district in San Ramon, California requires that all new developments that have pavement with grades above 15% have a skid resistant surface. The recently completed development has one street with an 18% grade. The city traffic engineer researched solutions and found the Tyregrip system to provide high skid resistance and ease of application.

Problem Statement

•Steep hill (18% grade) required high friction for emergency vehicle access during wet conditions.

•Tyregrip was selected for its skid resistance value.

•Contractor selected to apply system – Chrisp Co.

•Work-site evaluated and prepared for application

Installation process

•Work crew and materials staged

•Resin mixed 1:1 with simple tools

•Resin spread and coated with aggregate

Organized work crews apply approximately 210 x 15.5 ft. in 2 ½ hours.

Aggregate leveled with simple tools

Road is ready for traffic immediately after power sweeping

City of Bellevue Forest Drive, 15% grade on ahorizontal curve leading to a stop light. Flashing warning signs and directionalarrows to warn drivers of the danger had been erected in an effort to reduce crashes with no result.

Forest Drive in early 07, still no reported crashes.

Inspection made in May 07 and still no crashes after a

harsh winter and the use of studded tires the surface of the

Tyregrip system retains its high friction function.

Road/Lane departures

Penn DOT Tyregrip ProjectNorthampton County

SB lane SR 611 south of Easton

District Eng Contact: Stephen

Pohowsky

Safety Program Specialist- Dist 5Penn DOT

#2 on Penn Dot safety projects listSharp right turn with vehicles skidding into NB lane during wet conditions2.48 crash rate includes head on, side swipe, hit fixed object, 3 deaths, 4 injury crashes, and 20 total crashes in 8 years

Avg. surface skid resistance before 33

Avg. surface skid resistanceafter – TBD by end of June

City of Bellevue Forest Drive, 15% grade on ahorizontal curve leading to a stop light. Flashing warning signs and directionalarrows to warn drivers of the danger had been erected in an effort to reduce crashes with no result.

With an average pavement surface skid resistance reading of 33 the first course of action was to increase the pavements surface friction on the apex and approach to this dangerous curve

With heavy traffic from local communities plus being on a truck route a method of increasing the friction had to be chosen that could be installed quickly

Mr. Stephen Pohowsky, Safety Program Specialist Penn DOT decided to install the Ennis Paint Tyregrip treatment in early 2007 with the following desired goals:

*be installed by a Penn DOT maintenance crew within an eight hour period

*increase the pavement surface friction

*perform over a winter and survive carbon tipped snow plow blades

*reduce crashes

Penn DOT Tyregrip Project

Tyregrip installation on a negative cambered corner for the City of

Bellevue, WA. Crash reduction over 2 years reported by the city at 45

crashes prior to the installation and no crashes since the installation of

the Tyregrip system.

The Tyregrip treatment was installed on 600 linear feet of 12 foot wide roadway in less than 6 hours, including the application, curing and final site clear up ready for traffic

*the pavement surface friction reading taken by Penn DOT before the application was 33

* the pavement surface friction reading taken by Penn DOT after the application was over 95, installed June 13th, 2007

* the condition of the Tyregrip treatment after two winters of snow plowing is excellent

*no reported crashes or skid off the road incidents since the Tyregrip application.

Penn DOT Tyregrip Project

The curve on state route 611 before the Tyregrip treatment

After Tyregrip Installation

California Hwy 20 MP 29.6

District 3 Chief of Traffic Safety – Robert Peterson

Contractor – Chrisp Company

Traffic control provided by Caltrans Nevada City maintenance station.

Project completed September 2008

California Hwy 20

Problem statement

•Excessive road departures

•Downhill grade on tight curve

Timeline

•9:00 prep lane

•9:30 begin mixing resin

•9:35 apply aggregate

•Process is repeated until 480 lineal feet of lane completed

•12:15 application completed

Timeline (cont)

•2:15 roadway swept

•2:45 roadway opened to traffic

California Hwy 20 MP 29.6•Data to be tracked over time to gauge results

•First Caltrans safety project for multiple locations in the Sacramento area using HFST was advertised for contractor bids September 2010.

San Joaquin County

Tracy Blvd & Finck Rd.

•11 collisions in 3 years

•Mostly rear end collisions due to short stopping distances

Data

•System installed on July 10, 2007

•Two collisions in 12 months, compared to 11 collisions in three years, unrelated to conditions of blind turn.

ADT Count (7/11/2007)Tracy Blvd. s/o Finck Rd. NB – 4229 SB – 2872Tracy Blvd. n/o Finck Rd. NB – 3949 SB – 3059Finck Rd. w/o Tracy Blvd. EB – 210 WB – 204

The Tracy Blvd. bridge, crossing Old River, has a steep vertical curve that shortens the line of sight for vehicles leaving Finck Rd. heading north onto Tracy Blvd. Also, vehicles heading north on Tracy Blvd. approaching Finck Rd. have short stopping sight distance because of the vertical curve. Northbound vehicles waiting for clearance to make a left onto Finck Rd. have the potential of being rear ended by northbound vehicles not adhering to the advised speed reduction. There are numerous advance warning signs in both directions approaching this intersection but many drivers fail to slow down to the advised speed. The posted speed limit of Tracy Blvd. is 55mph but is reduced to 35mph over the bridge and at the intersection. During the past 3-years there have been 11 collisions at this intersection, 10 of which were due to issues involved with poor line-of-sight and vehicles failing to slow down to the advised speed over the bridge.Since the installation of Tyregrip there have been just two reported rear end collisions.

TyregripCaltrans Bay Bridge Installation

October, 2009•Prime Bridge Contractor: CC Meyers & Sons•Sub contractor and high friction surfacing system installer: Chrisp Company, Fremont, CA•Tyregrip materials: Standard Buff 1-3 mm crush Bauxite

Steel expansion plates

Problem Statement•The Oakland to San Francisco Bay Bridge is undergoing a complete reconstruction.•A temporary span was slid in over the Labor Day weekend, 2009.•Since then there have been a high number of crashes, one fatal involving a semi which flipped off the bridge deck.•Steel expansion plates caused vehicle skidding•Expansion plates were placed as part of temporary deck span.•Multiple car crashes•Unwanted media attention

Steel plates

Area Detail

Deck plate 10’ x width of bridge

Tyregrip installation

Lane closure of 3 lanes beginning at midnight.Installation process over night hours with full lane opening in early morning.

Area of installation and detail.

Tyregrip Updates

Kiewit Pacific – Devils Slide

Problem Statement•Kiewit Pacific is digging a tunnel on California Hwy 1, which closes frequently due to rock and mud slides during winter storms.•25% grade haul road coming out of tunnel•In wet conditions it was unsafe for the haul trucks, each weighing approximately 180,000 pounds fully loaded, to navigate the road where the rock from the tunnel was to be dumped.•Several vehicles had lost control coming back down the 25% grade.

Kiewit Devils Slide

• Solutions

– Increase Friction• Trial install November 2008

• Trial installation proved successful

Kiewit Devils Slide

Full Install•February 2009•Since then the entire haul road has been lengthened and surfaced with high friction treatment.•Materials – Dark Grey 1-3 mm crush Bauxite

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The royal palms blvd I-75 north horizontal curve ramp the

Tyregrip system was installed to increase the pavement

surface friction to reduce off road skidding crashes. Report

from FL DOT on surface friction number follows….

Figure 1. Test Location, Royal Palm Boulevard/ I-75 Northbound Ramp.

Table 1. Friction (FN40R) test results from the Royal Palm Boulevard/ I-75 Northbound Ramp.

Friction Number at 40 MPH (FN40R)

Northbound Ramp Southbound

Speed

Limit Mix Type

1 2 3 4 1 2 3 4

35* Tested on 4/11/06 25 FC-5

104 Tested on 5/23/06 25 Tyregrip

* Prior to friction resurfacing with Tyregrip.

Motorist Behavior – Royal Palms U& I-75

• Summary of motorist behavior at this location.

• Study was conducted by HNTB.

– Crash rate of 2.54 prior to installation.

– Crash rate of 2 in the 12 months following. Judged to be short window for conclusive evidence.

– Motorist speed was reduced by an average of 3.72 MPH in dry conditions and 2.62 MPH under wet conditions, this being the conditions judged responsible for a drop in the crash rate.

– There was a reduction in edgeline encroachment that accompanied the reduction in speed.

Questions?

Thank You