The purpose of this investigation was to examine the characteristics of outdoor recreational travel and to evaluate models of travel flow from population centers throughout the United States to outdoor recreational areas in Kentucky. Data were obtained by means of a license-plate, origin-destination survey at 160 sites within 42 recreational areas and by means of a continuous vehicle counting program at eight of these sites.

Among those characteristics of outdoor recreational travel which were examined in more detail were vehicle occupancies, vehicle classifications, and trip-length distributions. Vehicle occupancy was found to depend on the type of recreational area, distance traveled, and vehicle type. Occupancy increased with increasing distance and was greatest for those vehicles pulling camping trailers. Percentages of the various vehicle types were also influenced by the type of recreational area and the distance traveled. The proportion of camping units in the traffic stream increased with increasing distance of travel. In general, trip lengths were quite short as evidenced by the fact that 60 percent of all vehicles traveled less than 50 miles. However, trip-length distribution was highly dependent on the type and location of the recreational area. Analysis of the distribution of traffic over time verified that recreational travel is much more highly peaked than other forms of highway travel and, with the exception of holidays, is concentrated on Sundays during the spring and summer months. This time period appears most appropriate for the design of highways and parking facilities to serve recreational areas. It is highly recommended that future data collection programs be concentrated on the average summer Sunday to enable collection of the maximum amount of usable traffic data with a minimum of effort. Much of the data reported herein can be used in initial efforts to characterize travel to similar types of recreational areas outside of Kentucky.

In the modeling phase of the study, attempts to simulate distributed travel flows concentrated on various single-equation models, a cross-classification model, and gravity and intervening opportunities models. The cross-classification model was found to be an acceptable means for simulating and predicting outdoor recreational travel flows and was decidedly superior to the other models. From the cross-classification model, per capita distributed flows were found to 1) decrease at a decreasing rate with increasing population of the origin zone, 2) increase at a variable rate with increasing attractions of the recreational area, and 3) decrease at a decreasing rate with increasing distance. The intervening opportunities model was found to be unacceptable as a distribution model since it could not effectively accommodate the widely differing sizes of the 42 recreational areas. The gravity model, on the other hand, was quite effective in distributing actual productions and attractions. Problems associated with the gravity model were limited to difficulties in accurately estimating trip productions and attractions in the trip generation phase of analysis.

Report Date


Report Number

No. 369

Digital Object Identifier



Prepared for presentation at the 43rd Annual Meeting Institute of Traffic Engineers, August 19-24, 1973, Minneapolls, Minnesota.