The City of Lincoln, Nebraska, with a current population of 207,100 is growing at about 13% each year. Increasing traffic volumes are a growing concern to public officials and citizens alike. The streets serving the older sections of the city are of particular concern because of the divisions of opinion regarding the need for and extent of widening these streets. The Mayor appointed a citizens task force to study the need for traffic improvements on five key segments of these streets and recommend a program for improvement. Many of the task force members questioned the viability of the transportation modeling used by the city. The task force sought a congestion measure which could be applied (as a matter of public policy) to determine when, and to what extent, improvements would be made to these streets; i.e., the label "trigger mechanism" was used. The measure of congestion agreed upon by the task force was "average travel speed" along these streets. This measure was used to determine the level of congestion and to establish threshold values which would "trigger" successive levels of improvement; e.g., parking removal, turn restrictions, traffic signal timing, intersection widening, and lane additions. (A)
Abstract