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Use/Demand

Use/Demand. Concepts/units Methods Use in Planning Management/operations Evaluation Needs assessment Forecasts. Why Measure Use. Operational decisions maintenance, staffing, budget allocations Needs Performance measure/evaluation. What to measure.

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Use/Demand

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  1. Use/Demand • Concepts/units • Methods • Use in Planning • Management/operations • Evaluation • Needs assessment • Forecasts

  2. Why Measure Use • Operational decisions • maintenance, staffing, budget allocations • Needs • Performance measure/evaluation

  3. What to measure • Use units – individual, groups…visit, visitor, trip, day, RVD, vehicle entry,… • Level of detail/aggregation • Temporal • Spatial • By activity • By user characteristics

  4. Use estimation questions • Measure or estimate use at existing site • Forecast use at existing site • Forecast changes in use • New sites/products • Change at site or within the environment

  5. Key determinants of use • Population size & characteristics • Distances to markets • Tastes & preferences • Prices • Substitutes • Quality/quantity of supply • Promotion/information • Weather/climate

  6. Methods for estimating use • On-site techniques • Counting devices • Observation • Surveys (sample or census) • Off-site • Use prediction Models – e.g. Gravity model • Trip generation • Trip distribution

  7. Double Sampling Technique • 1. Select a variable that is easily measured • E.g. water meter - W • 2. Establish a relationship with use • U = a * W + c • Calibration via “double sampling” /linear regression • U = 1/3 * W - 2 • 3. Regularly measure W and apply equation • 4. Periodically recalibrate See page 21 of lecture handouts for details

  8. Sampling to estimate use • Stratify time periods into H, M, L use • E.g. weekend, weekday, am, pm, eve • Sample representative periods within each stratum • Measure use during each sampled period, compute averages • Expand from sample to population

  9. Lansing Trail Strata:Use counts for one hour Overall avg = 42,Total use = 42 *12 hours*31 days = 15,624

  10. Gravity Model • Ti,j = K* Pi *Aj / D2ij • Where • Ti,j = trips from origin i to destination j • Pi = population of origin I • Aj = measure of attractiveness of destination j • Dij = distance from i to j (or cost) • K =calibration constant

  11. Linear regression model • V = a0 + a1 X1 + a2 X2 + a3 X3 +… an Xn • Where • a’s are coefficients to be estimated • X’s are independent variables/use predictors • E.g. V = participation rate • Frequency of participation • Visits in past year • X’s : age, income, gender, location, weather…

  12. Demography • Forecast size, geographic distribution, and age-sex composition of the population • Census 2000 data • American Fact Finder

  13. Participation by demographic characteristics • Age • Income • Gender • Rural/urban, location • Racial/ethnic group

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