Professor Habib Alshuwaikhat

Trends in Urban Transportation

Since World War II, per capita ownership of automobiles in US has more than doubled, partly because of the increase in real income.

Increases in automobile ownership have gone in hand with the process of suburbanization, each reinforcing each other.

In terms of direct cost, private transportation more or less pays for itself, where public transportation requires heavy subsidization.

Prof. Alshuwaikhat - KFUPM - CP101 2

Transportation Planning and Land Use

The decline in public transportation since WW II was attributed to: increased automobile ownership and more spread-out pattern of land use .

The present pattern of land use shapes the present demand for transportation, and transportation investment decisions shape the future pattern of land use.

Land use and transportation planning proceed as coordinated rather than isolated processes.Prof. Alshuwaikhat - KFUPM - CP101 3

The Transportation Planning ProcessThe goal is to assist governments in

providing an adequate transportation system at an acceptable cost.

This involves modeling the behavior of the present system, estimating future travel demand, and estimating how changes in the system will affect travel behavior and operation of the transportation system in the future

Prof. Alshuwaikhat - KFUPM - CP101 4

The Transportation Planning Process

Large scale transportation planning is a four-step process:

1. Estimating trip generation2. Estimating trip distribution3. Estimating modal split4. Trip assignment

Prof. Alshuwaikhat - KFUPM - CP101 5

The Transportation Planning Process

1. Estimating trip generation: without considering destinations the planers, using such variables as household size, household income, and number of vehicles per household, estimate the total number of trips that will originate from each zone

2. Estimating trip distribution: using a gravity model or other mathematical model, the planners will then estimate the number of trips from each zone to each zone.

Prof. Alshuwaikhat - KFUPM - CP101 6

The Transportation Planning Process

3. Estimating modal split: if more than one mode of transportation is available, say automobile and bus, the planners will use mathematical models to estimate the number of travelers using each mod from each origin to each destination. The main variables is such models are cost and travel time.

4. Trip assignment: where there is more than one route from one zone to another zone, the final item to be modeled is the number of trips that be will be made via each route.

Prof. Alshuwaikhat - KFUPM - CP101 7

How the Four modeling Steps are Used?

First, the existing state of the transportation system id modeled mathematically, using the 4 steps described.

Model Calibration: Then the model is calibrated to produce results that correspond to the actual flow of traffic.

Once the model duplicates the observed travel behavior, alternative situations can be modeled. For example, a planner might assume an increase in the number of households in a given zone.

Prof. Alshuwaikhat - KFUPM - CP1018

Benefit /cost analysis is frequently used to evaluate and rank investment possibilities.

Ultimately, though, deciding on major investments is a political matter because transportation system investments can have a large consequences for land values, neighborhood quality and the entire pattern of development.

In US context, and from the planner's perspective, the most important federal imitative in transportation was the Intermodal Transportation Efficiency Act (ISTEA) of 1991 : coordination between transporting planning and urban and regional planning

Prof. Alshuwaikhat - KFUPM - CP101 9