The Fourth Edition of Parking Generation was recently published during the fall of 2010. This is an update to the Third Edition, published in 2004. Sixteen land uses were added to Parking Generation, which brings the number of land uses with parking datasets to 106. A total of 450 parking studies were added to Parking Generation, enhancing the datasets of many of the land uses included in the Third Edition. Some land uses, like shopping centers, have datasets that include parking data by time of day and month of year (most significant is the data from the Holiday shopping season versus data from the rest of the year).
Traffic engineers typically design a site’s parking supply to match the 85th percentile peak parking rate. This means 85% of sites will have peak parking at or below this rate and typically gives a safety factor versus just using the average peak parking rate. Table 1 compares the 85th percentile peak parking rates from the Third Edition to the Fourth Edition at common land uses. Stay tuned – I plan to post a spreadsheet later this fall with the average and 85th percentile rates for all of the land uses in the Fourth Edition this fall.