Trip and parking generation at transit-oriented developments: a case study of Redmond TOD, Seattle region

25 26 Standard guidelines for trip and parking generation come from the Institute of Transportation 27 Engineers (ITE). However, their trip and parking manuals focus on suburban locations with 28 limited transit and pedestrian access. This study aims to determine how many fewer vehicle trips 29 are generated at transit-oriented developments (TODs), and how much less parking is required at 30 TODs, than ITE guidelines would suggest. 31 32 In the travel literature, developments are often characterized in terms of D variables. The five 33 TODs studied in this project are more or less exemplary of the Ds. They are characterized by 34 land-use diversity and pedestrian-friendly designs. They minimize distance to transit, literally 35 abutting transit stations. They have varying measures of destination accessibility to the rest of the 36 region via transit. Three have progressive parking policies, which fall under the heading of 37 demand management. Two have high residential densities, and one has a high intensity of 38 commercial development. 39 40 Simply put, TODs (even the most auto-oriented) create significantly less demand for parking and 41 driving than do conventional suburban developments. With one exception, peak parking demand 42 in TODs is less than one half the parking supply guideline in the ITE Parking Generation 43 manual. Also, with one exception, vehicle trip generation rates are about half or less of what is 44 predicted in the ITE Trip Generation Manual. 45 46 Reducing the number of required parking spaces, and vehicle trips for which mitigation is 47 required, creates the potential for significant savings when developing TODs. Guidelines are 48 provided for using study results in TOD planning. 49 TRB 2017 Annual Meeting Original paper submittal not revised by author.