Overview
The last systematic surveys of trip generation from parking sites in Switzerland date back to the year 1983 (SVI FA 10/81 "Management of parking spaces as a means of directing traffic", Glaser + Saxer). In the last 25 years, car ownership has increased significantly (1990: 4393, 2006: 5161), and traffic behaviour has altered. As a result of changes in so-ciety and a change in the external general conditions, it can be assumed that the volume of traffic from parking sites has changed since the last survey. However, there are no new figures on this subject, or they are only known from individual case studies.
Traffic-intensive facilities are buildings and sites with a high frequency of visitors or customers the whole year round, namely facilities in the health care (hospitals) and educational (universities, colleges, vocational schools) sectors. This research concentrates on facilities used throughout the whole year, and both traffic-intensive services (supplement to SVI 2001/545) and other uses (work, retail trade) that are not considered to be traffic-intensive.
The previously defined characteristic traffic values enable the description of the trip production of the various types of use. The most important characteristic values are "Car journeys/100m2 gross floor area as well as "Car movements/parking place/day".
The research project has the following objectives:
- Determining the traffic volume of parking facilities for non-intensive public utilizations. Core sizes of traffic by parking facilities are e.g. traffic generation rates, load curves, car occupancy levels. The assessment shall also ensure public parking facilities.
- Development of a land use and its associated parking facility. These include determining the influencing variables that define these types as well as the development of methods and parameters to define their influence on demand (PW-rides, parking).
- Preparing the findings for the planning process. This includes in particular the drafting of the new VSS standard 640 283 'parking: traffic'.
The definition of terms is followed by extensive research of literature in Switzerland, Germany and Austria. The literature is systematically analysed according to previously defined characteristic traffic values. On the other hand, the study deals with concrete model cases in German-speaking and French-speaking Switzerland. For 35 model cases, the information from the people re-sponsible was analysed and, to some extent, completed by our own surveys. The charac-teristic traffic values for the different uses result from these analyses.
Funding
Results
Given all the uncertainties because of the unsatisfactory data records available, the following main findings can be established:
- The trip generation is primarily determined by the user.
- The most traffic-intensive use is sales (shopping centres).
- Uses related to employment generate rather little traffic, which is, however, mainly concentrated during the rush hour periods in the mornings and evenings.
- The modal split between uses differs considerably. Weekly time variation curves are, as a rule, evenly balanced over weekdays with slightly lower values on Fridays, and substantially less traffic at weekends. One exception is sales, where the traffic volume increases significantly at weekends, with the highest values on Saturdays.
Other results
Statements on the characteristic traffic values required were found in 16 sources. The rather sparse data records available therefore indicate that the uses observed, as opposed to traffic-intensive facilities such as shopping centrums, have hardly been disputed and therefore up to now have hardly ever been systematically investigated.
On conclusion of this work, the data records as regards the traffic generation of parking facilities are to be regarded as unsatisfactory. There are gaps, and in particular in the case of time-variation curves, incidence of journeys, as well as numbers of customers and visitors. The reasons for this are, on the one hand, that we are dealing with uses with little traffic intensity, where the trip generation up to now has scarcely been picked out as a central theme, and, on the other hand, that characteristic traffic figures are not of significance for the operation of these facilities and therefore from the operator's point of view, there is no interest in surveying them. Each of the 35 examples is documented on a data sheet. This figure is barely adequate for a differentiation according to type of use, whereby statements are also dominated by individual cases.
The distinct characteristic traffic values according to type of use were derived from the analysis of sample cases and research in literature. They are defined as a bandwidth with the exclusion of extreme values. While using them it should be taken into consideration that only low numbers of case figures back up these values and consequently they should be regarded more as simply guide values and indications, as well as being flawed by uncertainties.
Characteristic trafic values are in the final report (attached).