Congestion Buster Task Force

Frequently Asked Questions

What is congestion?
In simple terms, congestion is the situation that results when travel demand approaches or exceeds the capacity of a transportation facility to provide service at performance levels acceptable to the users. This definition applies not only to highway facilities but also to transit, pedestrian and bicycle facilities as well.

What are the two main types of congestion?
Recurring congestion, which occurs on a regular basis, typically in the peak hour, is caused by heavy demand trying to use a facility at the same time.

Nonrecurring congestion is caused by random, but not infrequent, events that disrupt traffic flow, such as vehicle breakdowns, accidents, construction work zones and weather. Nonrecurring congestion is generally credited with causing half of the total roadway system delay.

What factors contribute to congestion?
Many factors may influence congestion. These factors can range from, when and by which mode people choose to travel, to how much capacity there is on a given transportation facility. Put simply, congestion is influenced by both the supply of transportation facilities and demand for the use of transportation facilities.

What is travel demand?
Travel demand is the movement of people and goods. Factors that influence the movement of people include: number of households, household size, gender, age, income, licensed drivers, available vehicles, vehicle occupancies, length of trip, mode of travel, and time of travel.

Demand varies by month of the year, day of the week, and hour of the day. The link between land use and transportation is fundamental to understanding travel demand: trip patterns, volumes and mode choice are largely a function of land use.

Suburban growth and the decentralization of activities to suburban areas contribute to longer trips, additional local trips and less transit options. Over the long run, land use can greatly influence regional travel patterns. Avoiding future congestion, therefore, requires careful attention to zoning and land use plans, in coordination with the strategic provision and pricing of transportation services to influence where development occurs.

What is transportation supply?
Transportation Supply is the capacity of transportation facilities. Some factors influencing highway capacity are: number of lanes, lane width, nearest physical obstructions, design speed, the composition of vehicles in the traffic stream (e.g. cars vs. trucks), steepness of grades, signal timing, parking, access points, turning movements, geographic location and pedestrian movements.

Transit capacity can be even more complex and deals with the movement of both people and vehicles. Some factors affecting capacity are: the number and type of transit vehicles, passenger capacity, the headway or spacing of vehicles, passenger loading and unloading characteristics and the quality and type of stations and stops.

How do we measure congestion?
A number of different congestion measures have been proposed in literature or used in practice. Many studies and users recommend travel time based measurements such as, delay or travel time/speed. One recent study reported that the average New Jersey motorist spent 36 hours a year in congestion in 1999 compared to 11 hours in 1982.

Other commonly used measures of congestion include Level of Service (LOS), Volume/Capacity Ratio (V/C) and Vehicle Miles of Travel (VMT). These measures are frequently used because of data availability and ease of understanding. Congestion indices, such as the Roadway Congestion Index (RCI) or the Travel Rate Index (TRI) are also being used to measure congestion on the regional level.

Most recently, the cost of congestion has become an important measure. In 1999, a study reported the cost of congestion for Northern New Jersey was $595 a year - up $40 from 1998.

Separate measures are often used for highway and transit. Performance measures for transit are typically based on the service area and the type of service provided, such as in-vehicle travel time, load factor and frequency of service.

Are there standards for measuring congestion?
Since congestion is based on one's perceptions of acceptable conditions, performance standards may vary by type of transportation facility, geographic location, time of day and trip purpose.

What trends can impact congestion?
The following trends and observations could affect future travel in New Jersey.

Population
New Jersey's population is forecasted to grow by more than 1 million people and 800,000 new jobs over the next 20 years. Increases in population and employment will result in greater travel demand. Aging Baby Boomers comprise the largest segment of New Jersey's population. In the next 20 years, a large and rapid increase in the number of seniors is likely to change the characteristics of travel demand.

Household
In New Jersey, there are more households but smaller ones, more households that comprise people who are not related, fewer households with married couples and more single-parent households. These characteristics typically increase demand for travel.

Income
New Jersey has the highest per capita income in the nation. High incomes typically correlate to more trips, higher auto ownership rates and to longer commutes.

Vehicles
There are more vehicles registered in New Jersey than licensed drivers. On average, there are two vehicles for every household in New Jersey and 1.5 vehicles for every job.

Miles
The number of Vehicle Miles of Travel (VMT) continues to grow, but at a slower rate in recent years.

Network Travel
Will increase as a share of total daily trips.

Tourism
New Jersey's $30 billion tourism industry, our second largest, generates 635,000 jobs, $2.2 billion in taxes and 164 million annual travel and tourism trips. The geographic and seasonal distribution of NJ tourism has geographic implications of congestion, especially as it relates to shore communities.

Work Hours
More companies are offering flexible work hours. Telecommuting/working at home are increasingly popular options for reducing travel demand.

What are the consequences of congestion?
Consequences can include local traffic impacts, stagnant economic growth, limited community access, reduced quality-of-life, highway safety concerns, environmental degradation and increased energy use.

Can anything be done?
Yes, the Congestion Buster Task Force is being formed to address the challenge of congestion in New Jersey. There are proven techniques that can be used to deal with specific congestion problems, as well as transportation and land use strategies that can be implemented to enhance mobility and accessibility. Many of these techniques and strategies require changes to individual travel behavior, persuasive use of land use management techniques, changes in institutional structure, garnering of political will and/or increased funding. The Task Force will recommend steps to manage the growth of trips and vehicle miles traveled. What are some strategies?

The following are examples of strategies that can be employed in a mobility/congestion reduction program:

The following are examples of strategies that can be employed in a mobility/congestion reduction program:

Demand Management
Travel Demand Management (TDM) strategies are designed to reduce the demand for transportation services, usually concentrating on reducing single occupant vehicles and decreasing demand during peak hours. They may include:

Alternative Work Schedules
Alternative Modes
Alternative Work Locations
Congestion Pricing
Employee Support Programs
Parking Restrictions
Staggered work hours
Telecommuting
Ridesharing (Carpooling/Vanpooling)

Supply Management
Supply strategies generally increase the capacity or efficient use of facilities. They can be:

Intelligent Transportation Systems
Incident Management
Transit Facilities and Services (Capacity)
Intermodal Facilities - Park and Ride
Traffic Engineering - signal timing, layout and synchronization
Highway Capacity increases
Bike/Walkways

Land Use Management
Growth Management has the potential to limit total travel demand on the transportation system. It includes:

Planning & Zoning
Urban Design
Mixed Use
Density

Reference:
M. Meyer, ITE, A Toolbox for Alleviating Traffic Congestion and Enhancing Mobility, 1997