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Increased peak period congestion causes the peak to spread. The travel time impact of congestion is mitigated for some travelers, but the inconvenience of traveling at a less preferred time also has a cost. Alternatively, increases in highway supply narrow the peak. This reduces the travel time savings, but it generates a benefit for those traveling closer to their preferred times. This benefit from roadway supply increases has been ignored in practical applications, largely due to the difficulty of quantifying the effect. This paper reports on an attempt to quantify the peak narrowing effect of increased highway supply. For the morning commute, the model estimates that each 1% increase in lane-miles per thousand population results in workers departing from home about 0.06-0.09% closer to the peak time.

The paper presents a methodology for forecasting freight flows over regional transportation networks. This methodology may be used by state departments of transportation (DOTs), metropolitan planning organizations (MPOs) and county transportation planners as a planning tool for identifying the most heavily traveled links of transportation networks and determining the direction of flow for major commodity groups. The model may also be used to estimate the major routes for movement of hazardous materials and to ascertain the impact of freight flows on pavement maintenance. Application of the methodology to the state of New Jersey indicates that the most heavily freight-flow utilized routes are Interstate 80, New Jersey Turnpike, and Route 202. [ABSTRACT FROM AUTHOR]

This article explores the meaning of congestion on highway-type rural and suburban facilities, such as tollways and freeways, and develops congestion thresholds, above which it will be necessary to add lanes to specific sections of these facilities. The study originated from the need for the development of a tender for a major tollway facility in Israel. It was necessary to clearly identify the conditions at which the flow could be termed "congested," in the sense of lower levels of service, dense flows, and tense driving conditions. Several congestion measures for the defined purpose were explored. In the end, density of flow and the resulting flow rate were found to be the most appropriate measures. Based on the measures selected, specific thresholds were developed for four-and six-lane rural and suburban sections. The measures presented are dependent primarily on the percentage of heavy vehicles. It is assumed that the conditions of the facility are "ideal," meaning a high design speed, level terrain, and wide lanes and shoulders. An example is presented and evaluated of the estimation of a nonlinear growth curve for a rural section of a tollway facility and the approximate time at which the congestion threshold will be crossed. [ABSTRACT FROM AUTHOR]

The discomfort and dangers experienced on Rome's crowded street led Julius Cesar to issue a traffic ban ordering unnecessary vehicles off the streets during daylight hours. It appears that congestion continued in Rome, as it did in many other European cities, as population grew and particularly after private horse-drawn vehicles came into fashion centuries later. A recent comparison of conditions in 50 urbanized areas in the United States found that congestion appears to be getting much worse in most of the regions studied. The greatest increases occurred in Salt Lake City, utah, wher congestion increased by 31%. In addition, congestion increased by 15% to 20% in Columbus, Ohio and in Cincinnati, Ohio.