RELIEVING CONGESTION

Keeping the Nation’s Arteries and Travel Ways Unclogged

~Anyesha Mookherjee

Traffic Engineer, URS Corp

The Text Book Definition

“Traffic Engineering is that phase of transportation engineering which deals with the planning, geometric design and traffic operations of roads, streets, and highways, their networks, terminals, abutting lands, and relationships with other modes of transportation.”

Traffic Engineering by Roess, Prassas and McShane

What it Actually Means

Provide transportation from point A to point B that is: Safe Fast Comfortable Convenient Economical Environmentally Compatible

Congestion

Congestion results when traffic demand approaches or exceeds the available capacity of the systemCongestion on roadways leads to

Increased frequency of crashes

Increased average trip times

Increased fuel consumption

Increased green house gas emissions

Leading Causes

According to FHWA (Federal Highway Administration), the leading causes of congestion on US roadways are

Bottlenecks Traffic Incidents Work Zones Bad Weather Poor Signal Timing Special Events

Leading Causes of Traffic Congestion in the US

5%5%

15%

10%

25%

40%Special Events

Poor Signal Timing

Bad Weather

Work Zones

Traffic Incidents

Bottlenecks

The Congestion Relief Toolbox

Improve Service on Existing Roadways

Add Capacity

Electronic Toll Collection and Pricing

Better Work Zones

Travel Options

Traveler Information

Improving Service on Existing Roadways

Access ManagementTraffic Incident ManagementTraffic Signal Timing

Access Management

At urban intersections separate out the critical turning volumes and provide exclusive turn lanes

Major street with shared left through movements causes through vehicles to queue behind left turning vehicles

Major street with dedicated left turn lanes movements removes left turning vehicles from the paths of through vehicles

Access Management

Channelize heavy/critical turning movements

Traffic Incident Management

Improve response time for first responders to roadway crashes

Provide breakdown lanes

Centralized traffic management centers

Provide real time data about crash via Highway Advisory Radio (HAR)/AM and FM radio/TV/Highway signs

Traffic Incident Management - A Real Time Example

Traffic Incident Management-A Real Time ExampleTimeline of EventsJanuary 13, 2004 - Tuesday2:45 p.m. Tanker truck explodes on I–95, closing interstate in both directions2:46 p.m. Patroller alerts Maryland State Highway Administration (MSHA) of incident2:47 p.m. Patroller begins turning vehicles around at the scene. 2:54 p.m. Electronic message signs changed on I–95 to inform motorists that the interstate near Baltimore is closed. Traffic redirected to alternate routes3:06 p.m. First fire department arrives on the scene 3:45 p.m. The majority of the fire is under control7:00 p.m. Two of the four lanes of southbound I–95 reopen. 11:30 p.m. All lanes of I–895 reopen

January 14, 2004 - Wednesday1:30 a.m. Fire crews wash down roadway2:15 a.m. Southbound lanes of I–95 reopen3:35 a.m. Northbound lanes of I–95 reopen

Two firefighters work to control the flames on a tractor trailer that was caught in the

explosion of the fuel tanker

Traffic Signal TimingPre-timed signals vs. actuated signals

Loop detectors Camera detectors

Optimization of cycle length

Synchro/SIMTrafficSystemization of signals within corridor

Interconnect signals Optimize network using

Synchro/SIMTrafficAdaptive traffic control systems

Split Cycle Offset Optimization Technique (SCOOT)

Add Capacity

Construction of additional traffic carrying lanesAdditional freight rail and light rail serviceIncorporate pedestrian paths and trails

Capacity Improvement – Woodrow Wilson Bridge Project

The original bridge was opened to traffic in 1961.Was designed to carry 75,000 vehicles per day in the year 2020Currently carries 195,000 vehicles per day and is projected to carry 295,000 vehicles per day by 2020Existing six lane configuration inadequate, causes seven hours of congestion and several mile long backups daily The drawbridge opened 260 times a year

Woodrow Wilson Bridge Project

New span will have Ten lanes of traffic to carry I-495 traffic Two lanes for future rail use in the median 20 feet higher, will only open 65 times a year after

completion

Electronic Toll Collection (ETC) and Pricing

ETC is a technological implementation of a pricing concept using RFID transponders mounted in vehiclesIt determines whether the cars passing are enrolled in the programIt alerts enforcers for those that are notIt debits electronically the accounts of registered cars without their stopping, or even opening a window

Electronic Toll Collection (ETC) and Pricing

High Occupancy Toll (HOT) lanes: On HOT lanes, low-occupancy vehicles are charged a toll, while High-Occupancy Vehicles (HOVs) are allowed to use the lanes for free or at a discounted toll rateVariable Pricing: Pricing on toll

facilities are varied by time of day with the intention of encouraging some travelers to:

use the roadway during less congested periods shift to another mode of transportation change routes

Better Work Zones

Plan aheadUse available traffic models to predict effect of closing traffic lanes on queuesRestrict lane closures to off peak and weekend hoursInvolve the community. Get the word out

Travel Options

Travel Demand Management Special Events Traffic Management

Travel Demand Management

Evaluate the effect of new development on existing roadway systemPlace the onus of mitigating congestion caused by new traffic on developerProject traffic demand based on land use and plan accordinglyProvide traveler with options:

Tax incentive for transit Park and ride Share-a-ride

Transportation Demand

Transportation Facilities

Land Use

Parades, games, seasonal tourism can place a sudden burden on the roadway system

Easy to plan ahead as event is not of an unexpected nature

Community and police involvement essential

Detour traffic through alternate routes

Establish a system of one-way routes

Establish more parking

Special Events Management

Traveler Information

Creation of 511 for traffic, similar to 911 for emergencyDynamic Message SignsReal Time Travel Time Information Web based Radio based TV based

Real Time Travel Time Information

Screenshot of traffic conditions in area highways on September 18th 2007 at 5:00 PM from www.traffic.com

In a Nutshell…

No one strategy can solve the

congestion problem

Questions Anyone?

Useful websites: www.fhwa.dot.gov www.islandnet.com/~litman www.wilsonbridge.com www.chart.state.md.us/ www.trafficware.com/articles.html

Feel free to contact me at amookherjee@sha.state.md.us