Lane Departure Countermeasures · Lane Departure Countermeasures •Countermeasures to reduce...

Lane Departure Countermeasures

Gevin McDaniel, P.E. and Ed Cashman, P.E.

Lane Departure Safety Plan Overview

Types of crashes considered as Lane Departure:

•Centerline cross-over

• Failed to keep proper lane (e.g. Sideswipe)

•Run off the road (ROTR)

•Wrong-Way/Wrong-Side

Lane Departure Safety Plan Overview• Florida is an FHWA

Focus State for Lane Departure

• FHWA assisted with the development of the Lane Departure Safety Plan

• Lane Departure is an Emphasis Areas of the Florida Strategic Highway Safety Plan

Lane Departure Safety Plan OverviewAvg: 1,188/year

2016 Statistics?1+????

Lane Departure Safety Plan Overview• I lost my brother-in-law in December 2016 to a lane departure

crash. He was struck by a vehicle leaving the roadway at night.

Lane Departure Safety Plan Overview• Low volume, straight, county road.

• Thermoplastic not used, paint no longer visible, RPMs no longer work properly…No maintenance.

• No visibility at night when vehicle headlights approach.


In Florida, from 2011-2013:

• 49% of all highway fatalities were the result of a lane departure crash

• A total of 3,513 fatalities from lane departure crashes over this 3-year period


Not only a State Road issue:

• Over 42% of the lane departure fatalities occur on Non-FDOT facilities

• FDOT must be proactive in working with the local agencies


Goal:• Save 140 lives per year over the next 10-year period• Request funding over the next 5-years• Implement tracking mechanisms to measure success• Engineering, Education and Enforcement (EEE)

• Education and Enforcement:• Targeted, frequent and high-visibility initiatives

• Speeding, Alcohol, Distracted and Unbelted Drivers

• Engineering: • Targeted, systemic deployment of cost-effective countermeasures

• Focus on higher fatality locations throughout the State• Opportunities in other programmed projects• District Safety Engineers will work with local agencies


• Countermeasures to keep drivers in their lane:• Pavement Markings

• Retroreflective Pavement Markings• Raised Retroreflective Pavement Markers

• Audible and Vibratory Warnings• Rumble Striping• Profiled Thermoplastic

• Enhancements for Curves: • Signing and Marking for Curve Delineation• Internally Illuminated RPMs• High Friction Surface Treatments for Curves

• Signing and Warning for Wrong-Way Driving


• Countermeasures to reduce severity of crash once drivers depart the lane:• Select Tree (or other hazard) Removal within Clear Zone

• Trees• Non-critical signs• Railings

• Wide Paved Shoulders• 5’ paved shoulders

• Safety Edge• Traffic Barrier Upgrades/Median Barriers

• Cable Barrier• Guardrail• Concrete Barrier

Pavement Markings

• Longitudinal Pavement Markings are the most basic form of lane departure countermeasure

• The retroreflectivity of these markings are critical to their effectiveness

• Raised Retroreflective Pavement Markers (RPMs) supplement the longitudinal lines and improve wet/night visibility

• Maintenance of pavement markings and RPMs is just as critical

Pavement Markings

Beads too Low Beads too High Optimal Embedment

Rumble Striping

• Rumble Strips are the most effective countermeasure for lane departures

• July 2015, Implemented Rumble Striping• Aggressive design

• No criteria for context consideration

• Received numerous complaints of noise pollution

Rumble Striping

Rumble Striping

• Released Roadway Design Bulletin 16-07 (08-19-16)• Removed existing Index 519 (Rumble Striping)• Used Index D519 to further develop Rumble Striping

• Reduce Noise Pollution• Accommodations for Bicyclist

• Required all projects in Design Phase to come to Central Office for review of context• Changes to Contract Plans if required• Use of new Index D519

• Released DCE Memorandum 11-16 (08-23-16)• All projects let prior to March 1, 2017 to come back to Central Office for

review of context• Changes to As-built plans if required• Use of new Index D519

Rumble Striping

NCHRP Synthesis 490:

Noise Pollution significantly reduced when located outside of a 650 ft radius from a residence

Rumble Striping

Old Edge Line Pattern

New Edge Line Pattern

Rumble Striping

Old Edge Line Pattern New Edge Line Pattern

Rumble Striping

Old Center Line Pattern

New Center Line Pattern

Rumble Striping

Old Center Line Pattern New Center Line Pattern

Rumble StripingOld Depth

Rumble StripingNew Depth

Rumble Striping

• District 2, Rumble Striping Pattern Test Project:• 5 different patterns were tested, including two Sinusoidal Rumble Striping

patterns• Various depths of cylindrical pattern• Two versions of sinusoidal patterns

• 1000-ft runs of each pattern• Noise Study conducted• Evaluated relative decibel levels

• Recently Installed (Go ride them for yourselves)!!

• Study recently finalized

• Drafting new Criteria soon

Rumble Striping

Rumble Striping Pattern Test Project Location: District 2; Suwannee County, US 90Exit 275 (Live Oak/Lee)

Rumble Striping

Rumble StripingRumble Striping Pattern Test Project Layout:Go drive it for yourself, have passenger use this layout to know what you are experiencing

Rumble Striping

Measuring Noise Levels – FDOT State Materials Office:

Rumble StripingMeasuring Noise Levels – Consultant:

Rumble Striping

10.9

6.67.3

4.6

00.7

1.2

11.82

6.22

10.62

6.22

1.02 0.82

2.72

0

2

4

6

8

10

12

14

Cylindrical, 8" Width and1/2" Depth




Sinusoidal, 8" Width and1/2" Depth

Sinusoidal, 8" Width and5/16" Depth

Profiled Thermoplastic, 6"Width

Ch

ang

e in

No

ise

(d

BA

)

Rumble Strip TypeChange in Noise (dBA) SMO Change in Noise (dBA) Consultant

Noise Evaluation Results

Rumble Striping

Rumble Striping

• Rumble Striping Policy Revisions• An imminent project in D2 will be installing 5/16” sinusoidal rumble strips

and 3/16” conventional rumble strips off the stripe.

• The developmental process is expected to be completed by the end of the year.

• The final policy will likely incorporate profiled thermoplastic, conventional rumble strips, and, potentially, sinusoidal rumble strips. Depending on roadway and roadside conditions, designers will pick the most appropriate treatment.

Rumble Striping

• Temporary Traffic Control Schemes?• Index 603, lane closure.

• Index 600 now allows for 3 mile lane closure for rumble striping projects.

• Other Solutions?• Flaggers riding in the back of a truck?

• Submitted NCHRP Problem Statement• Research on alternate TTC Schemes for slow mobile

operations.

Rumble Striping

• Developing retrofit to fill-in grindings

• Specific areas where residence experience extreme hardships due to noise pollution

• Targeting specific lines within 650ft radius

Rumble StripingTest project in District 3 for the use of Micro-Surfacing to fill the grinding

Rumble StripingMicro-Surfacing Retrofit: 02/14/2017 Location: District 3, Leon County, US 90

Rumble StripingMicro-Surfacing Retrofit: 02/14/2017 Grinding/Sweeping Existing Thermoplastic

Rumble StripingMicro-Surfacing Retrofit: 02/14/2017

Grinding to roughen surface and eliminate any loose thermoplastic

Grinding/Sweeping Existing Thermoplastic

Rumble StripingMicro-Surfacing Retrofit: 02/14/2017 Tack Coating

Rumble StripingMicro-Surfacing Retrofit: 02/14/2017 Tack Coating directly over unground thermo

Rumble StripingMicro-Surfacing Retrofit: 02/14/2017 Filling Operation

Rumble StripingMicro-Surfacing Retrofit: 02/14/2017 Completed Product

Profiled ThermoplasticProfiled Thermoplastic Markings:

• Multilane: Used where paved shoulders are less than 1’-0” (Shoulder pavement durability)

• Two-Lane Two-Way: Used where there are no shoulders (MOT Constraints)

• Used near residential areas (Less noise)

Enhancements for CurvesStudy currently being conducted for the Department:

• Data collection using Curve Advisory Reporting Service (CARS)• Ballbank indicator• GPS receiver• Tablet collects and stores data electronically

• Video Data

• Inventory of existing signs and advisory speeds

• Determine if in compliance with the 2009 MUTCD• If not, plans will be developed to improve signing, marking and possibly

surface friction

Enhancements for CurvesEnhancements will include:

• Horizontal Alignment Warning Signs• Chevrons

• Arrows

• Advisory Speed Signs

• High Friction Surface Treatments

Enhancements for Curves• High Friction Surface Treatments

• Polish resistant aggregate in polymer resin binder

• Reduces horizontal curve lane departures• Average 32% reduction of total crashes

• Average 75% reduction of wet weather crashes

• Most effective in “tight” curves

• Recommended on curves where there is a crash history

HFST

Enhancements for Curves• High Friction Surface Treatments Performance:

0

10

20

30

40

50

60

70

80

90

100

0.000 0.010 0.020 0.030 0.040 0.050 0.060 0.070 0.080 0.090 0.100

Fric

tio

n N

um

ber

Texture-MPD (in.)

DENSE

OPEN

LGD

HFST

Roadside Hazards

Roadside Hazards• Does railing meet Clear

Zone requirements?

• What is the purpose?• Protect the root system of

the Pine Tree.

• P.S. Pine trees have tap roots…

• Is Pine Tree worth the cost, or reduced safety?

• What might happen whena vehicle impacts the railing?

Roadside Hazards• Results of impact with

similar Guiderail

• Horizontal members become spearing hazards

• Notice what is at the tip of the spear

• Thankfully, nobody was injured in this crash

Roadside Hazards• Although sign supports are “crashworthy”, may not be impacted as

crash tested

• This is hit was at an angle outside of the envelope of the crash testing

Safety Edge• Abrupt and deep drop-offs on edge of pavement may cause drivers to

overcorrect when reentering travel lane

• Caused by tire scrubbing the edge

Safety Edge• Safety Edge incorporates a 30 degree wedge into the edge of

pavement which reduces the potential for drivers overcorrecting

• Other benefits include:• Improves compaction on pavement edge

• Reduces Raveling, Cracking of the pavement edge

• Provides more aesthetic edge of pavement

Safety Edge• Florida Greenbook, Chapter 5 (Pavement Design and Construction):

Traffic BarriersDeflection Space vs. Impact Severity different barrier types:

• Flexible Systems – High Tension Cable Barrier• Capture and Redirect• High Deflection• Barrier Absorbs Most Energy

• Semi-Rigid Systems – W-Beam Guardrail• Contain and Redirect• Limited Deflection• Barrier and Vehicle share in the Dissipation of Energy

• Rigid Systems – Concrete Barriers & Traffic Railings• Redirects• Effectively No Deflection• Vehicle Absorbs Energy

Shape of Barrier Vehicle Roll and Climb

Traffic Barriers• Considerations when selecting barrier types

• PPM, Ch.4:

Traffic Barriers

Questions

Gevin McDaniel, P.E.

State Standard Plans Engineer

Central Office, Roadway Design

(850) 414-4284

[email protected]

Ed Cashman, P.E.

Standard Plans Engineer

Central Office, Roadway Design

(850) 414-4314

[email protected]

mailto:[email protected]

mailto:[email protected]

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