1. Mrs Lebogang Mogakabe M Tech (Student): Civil Engineering 10 July 2018
COMPARISON OF NEW PEAK HOUR TRIP GENERATION RATES WITH EXISTING RATES IN THE SOUTH AFRICAN TRIP DATA MANUAL
Mrs Lebogang Mogakabe
M Tech (Student): Civil Engineering
10 July 2018

2. OUTLINE Introduction Objective Methodology Results and Comparisons
Conclusion

3. INTRODUCTION
Peak hour trip generation rates are important for the calculation of the number of trips generated by a development during a peak hour, in South Africa (SA) these rates are obtained from the trip data manual documented in the Technical Methods for Highways (TMH 17)
TMH 17 acknowledges that the trip rates currently used in the country are based on insufficient data and in some cases international data that may not necessarily be applicable to South African conditions
A need thus arise to develop rates that are based on local conditions

4. OBJECTIVES
The main objective of the study is to develop peak hour trip generation rates that are applicable to use in the City of Tshwane (CoT) area for office developments and to compare them with rates currently used for offices
It is important to compare the current rates with the developed rates as a small difference in the trip generation rates could lead to either over estimation or under estimation of traffic generation and this could have a major impact on the transport decisions made by municipalities, provincial and national transport departments across the country

5. METHODOLOGY: Site Selection
Site selection procedures as prescribed on TMH 17 were followed and random visual site inspections were conducted to identify office developments already in operation
Due to insufficient resources only five sites located in the suburban area of the City of Tshwane (CoT) were selected to establish the base data for an extended study
Department of International Relations and Cooperation/Foreign Affairs
Office developments along Ingersol Street
Persequor Ext 10 and other office developments along Hotel Street,
Erf 10 and 11 Highveld
Office developments at Garsfontein/Mante intersection
The sites are used for professional, administrative and consulting services

6. METHODOLOGY: Survey Process

7. METHODOLOGY: Data Collection
Traffic counts were taken manually during AM, Midday & PM Peak hours at Soutpansberg/International relations, Mante/Garsfontein and Oak/Einstein intersections
Counts for Ingersol/Lois and Meiring Naude/Hotel intersections were obtained from City of Tshwane’s data base
The Gross Leasable Area (GLA) utilised in the calculation of trip rates was attained from internal and external town planners, traffic engineers and approved plans from CoT

8. RESULTS
Data was analysed using non-linear regression analysis to determine required peak hour trip rates and no trip adjustment/reduction factors were applied due to location of sites and minimal use of public transport
Summary of the trip rates for the 5 sites

9. RESULTS & COMPARISON

10. RESULTS & COMPARISON……..
The analysis results for Soutpansberg/International relations intersection (AM and PM ) were compared with the trip generation rates in TMH17 (AM – 2.1 and PM – 2.1 ) using the following equation:
𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑒𝑑 𝑡𝑟𝑖𝑝𝑠 = 𝐺𝑟𝑜𝑠𝑠 𝐿𝑒𝑎𝑠𝑎𝑏𝑙𝑒 𝐴𝑟𝑒𝑎 𝐺𝐿𝐴 ∗ 𝑇𝑟𝑖𝑝 𝑟𝑎𝑡𝑒 where GLA = size of the development (42 026m2)
Trip generation using existing rates = 883 trips for AM and 883 trips for PM peak
Trip generation using calculated (developed) rates = 193 trips for AM and 308 trips for PM peak

11. CONCLUSION
Trip rates for four of the five sites surveyed are low in comparison to the TMH 17 rates
Although errors in data for parameters factors such as land use, nature of trips, GLA and traffic counts might have an influence on the overall results of the study area, it must be noted that reliable techniques and sources were used to attain data and to carry out the analysis
It is however acknowledged that to make valid conclusions on the study a recommended minimum data set for 10 sites must be used, therefore these results must be considered a base which will be extended at a later stage once resources become available

12. THANK YOU!!!