Appendix B27 - Weekend and off-peak benefits

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1 Appendix B27 - Weekend and off-peak benefits

2 Technical Note Project Title: MVA Project Number: Subject: SY BRT Northern - BAFFB C3a556 Report A5b: Off-Peak and Weekend Benefits Note Number: 56 Version: 2.0 Author: Reviewer: Tony Barker John Allan Date: 19 August Introduction 1.1 Best and Final Funding Bids for Major Transport Schemes up to 2015 are due for submission in September For the economic appraisal of these schemes, the Department for Transport (DfT) has suggested that promoters should endeavour to claim benefits for each of the 8760 hours in a year. 1.2 For BRT North, a MSBC was submitted in 2010 that included scheme benefits covering weekdays plus for a portion of the weekends, the times when travel conditions are similar to the weekday inter-peak conditions. This was achieved by factoring the weekday benefits to account for the number of additional hours in a year that these conditions were considered to prevail, based on a comparison of traffic levels. 1.3 The DfT has suggested that any method for the BAFFB submission must account for the different journey purpose profile at weekends when there is very little employer s business travel. This is important because whilst the proportion of such travel is normally small even on weekdays, employer s time is valued much more highly in the webtag appraisal system one hour of employer s business time spent in-vehicle is worth over five hours spent by those commuting or for other purposes. 1.4 This note sets out a proposed methodology for estimating weekend benefits for the BRT scheme, taking account of travel conditions at the weekend including the lower number of employer s business trips. 1.5 The current version of this note contains two amendments that address comments, made by John Collins of DfT, on version 1.6. The first amendment simply makes it clear that weekend benefits will be calculated by flow-weighting individual journey purpose and mode combinations [see Paragraph 3.12]. The second amendment identifies correction factors that account for flow weighting capturing less than the full effect of the differences between weekday inter-peak flows and the flows in the weekend time-periods that they will be used to proxy. Appropriate congestion correction factors have been estimated from benefits calculated for individual hours of the weekday model [see Paragraphs 3.3 to 3.13]. Report A5b: Off-Peak and Weekend Benefits 1

3 2 Approach to Appraisal in SRTM3 for MSBC Tours 2.1 The Sheffield & Rotherham Transport Model 3 (SRTM3) works with tours that represent round trips. This is a more sophisticated approach to modelling than the usual origin-destination based models normally input to an economic appraisal. It requires a complex set-up of the DfT s TUBA software. 2.2 The SRTM3 bespoke Demand Model (SRDM3) uses nine outbound time-periods and nine return time-periods, covering all weekday travel between 0700 and 2300 (which accounts for more than 93% of all journeys made in a day): pre morning peak hour ( ); morning peak hour ( ); post morning peak hour ( ); inter peak period 1 (1000 to 1300); inter peak period 2 (1300 to 1600); pre evening peak hour ( ); evening peak hour ( ); post evening peak hour ( ); and off-peak period ( ). 2.3 Having so many time-periods available is helpful for finding weekday travel conditions that approximate to travel conditions at different times of the day at weekends. In particular, it is helpful to have the off-peak modelled because for much of the weekend traffic is lighter than the weekday inter-peak. 2.4 The tours represent journeys outbound in one time-period, returning in another or possibly in the same time-period but no earlier. Forty-five time tours are required to cover the day using the nine time-periods. For the appraisal, the forty-five tours are gathered into the ten macrotours that can be seen in Table In the table, the 45 tours are numbered individually in black in a normal font. For example, Micro Tour 19 represents travel outbound between 0900 and 1000 and return between 1000 and The 10 macro-tours, identified by large purple numbering and outlined in heavy black lines are shaded alternately grey and white. By way of example, macro tour 1 represents all the trips with both legs in the morning peak period (0700 to 1000), which includes microtours 1, 2, 3, 10, 11, and 18. Report A5b: Off-Peak and Weekend Benefits 2

4 Table 2.1 Macro-tours used in Appraisal and the Underlying Tours used in Modelling To Home Period From Home Time Period TUBA normally uses time periods that may be sub-divided into time-slices, for example the morning peak period may include three hour long time slices. To fit tours into this structure each of the ten macro-tours is set up as a time-slice and all ten are allocated to a single time period. Journey Purposes 2.7 The SRTM3 appraisal uses the following journey purposes: Home-based Employer s Business Non-home-based Employer s Business Commute Home-based Other Non-home-based Other 2.8 This journey purpose distinction is sufficient to enable the correction for employer s business trips required by the DfT. Report A5b: Off-Peak and Weekend Benefits 3

5 3 Proposed Approach to Appraisal for BAFFB Considerations for Development of Approach 3.1 The main feature of our proposed approach is to In TUBA, factor the weekday inter-peak demand by mode and journey purpose to match the weekend demand. In TUBA, select an appropriate weekday time-period to provide proxy generalised costs for each weekend time period the issue here is that the proxy costs should come from a time period with similar levels of PT service for PT costs and similar levels of congestion for highway costs. 3.2 In SRTM3, the shoulders of the weekday peak are modelled explicitly but in most models they would be not be. To avoid overestimating benefits in the shoulders of the peak, other scheme promoters will therefore need to factor down their shoulder peak benefits in a similar way. Levels of Congestion and highway benefits at the weekend 3.3 In estimating highway benefits for the weekend, it is important to consider weekday time periods with similar traffic flows because the benefits provided by a scheme are strongly influenced by the prevailing level of congestion the more congestion the greater the benefits we would expect. 3.4 It is worth remembering that travel conditions and therefore benefits, are not uniform throughout the day at the weekends. Analysis of automatic traffic counter data on the BRT route suggests that weekday inter-peak (1000 to 1600) traffic levels are roughly the same as those on Saturday between 1000 and 1900 and roughly the same as Sunday traffic flows between 1000 and Weekday off- peak flows (1900 to 2300 in the model) are similar to flows at other times during the weekend. This can be seen in Table 3.1, which uses depth of shading to highlight which weekend time periods the weekday time periods proxy.. Table 3.1 Average Hour ATC Flows and the Proxy Time Periods Time Period Weekday Sat Sun Sat Proxy Sun Proxy 0700 to OP OP 1000 to IP IP 1600 to IP OP 1900 to OP OP 2300 to OP OP 3.5 The weekday inter-peak proxy shown in the darker shading shows a reasonably good fit to each of the weekend time periods that it will proxy. However, the weekday demand is in each case little higher and work we have done to examine benefits for the individual hours in the Report A5b: Off-Peak and Weekend Benefits 4

6 morning peak period suggests that this level of difference needs to be addressed for in the estimate of benefits. 3.6 From Table 3.1 we can see that the ratios between the demand in our weekend time-periods and the weekday inter-peak proxy time-period are: Saturday daytime 0.94 [=2266/2369]; Saturday evening 0.89 [=2108/2369]; and Sunday daytime 0.86 [=1991/2369]. 3.7 Work we have undertaken to estimate the allowance for congestion levels indicated that: a demand ratio of 0.82 led to a congestion impact of 0.67; and a demand ration of 0.92 led to a congestion impact of These values were estimated by running TUBA separately for each of the three hours in the morning peak period. The TUBA runs used costs from the three individual hour assignments and the benefits were normalised by using the peak hour demand (by journey purpose) for each hour. The estimated benefits were summed across the journey purposes for the peak hour and both shoulder peak-hours. The benefits in the two shoulder peaks were divided by the benefits in the peak hour to give the congestion impact factors set out in the previous paragraph. 3.9 Interpolating gives the congestion impacts factors for the demand ratios that apply for the weekday inter-peak demand and the weekend time-periods for which we must estimate benefits. It is clear from the values set out in Table 3.2 that the congestion impact factors need to be applied to the benefits estimates the expected Sunday benefits are only 71% of what they would be with only flow-weighting. Table 3.2 Demand Ratio and Correction Factor to Apply to Highway Cost Differences Demand Ratio Impact of Congestion on Benefits 0.84 (Sunday Day) (Saturday Evening) (Saturday Day) Some of the weekend time periods will have benefits estimated from the weekday off-peak demand. This demand is a little lower than the Sunday evening peak demand but rather higher than any of the other weekend time periods it will proxy. It could therefore be expected that we would need to apply congestion impact factors in this case as well. However, the prevailing levels of congestion during the weekday off-peak are low, so it is expected that benefits arise mainly from providing shorter routes rather than reducing congestion. We therefore propose that congestion factors will not be applied to the benefits estimated from the weekday off-peak When choosing tours that represent the right traffic conditions, it is helpful to look back to Table 3.2 to consider the timing of the outbound and return legs Report A5b: Off-Peak and Weekend Benefits 5

7 Macro Tour 5 covers travel with both the outbound and return legs in the weekday interpeak Macro Tour 10 covers travel with both the outbound and return legs in the weekday offpeak 3.12 Table 3.2 summarises the weekend time periods and the weekday tours that will be used as a proxy in the cost-benefit calculations. Table 3.3 Macro Tour Used to Estimate Weekend Cost Differences Saturday Sunday 0700 to to to to Service Patterns and Public Transport Benefits at the Weekend 3.13 For public transport, the service pattern on a Saturday will be the same as Monday to Friday, but the service pattern on Sunday will be less frequent. We will use weekday inter-peak costs as a proxy for Saturday costs We intend to exclude the Sunday benefits from the calculations and exclude the Sunday operating costs as well. Thus, the benefits will be consistent with the operating costs but the Sunday benefits will not contribute against the capital costs of the scheme. This will yield a conservative estimate and since the operating costs are much larger than the capital costs, the estimate will not be too far short of the real total. Journey Purpose 3.15 To account for the low proportion of employer s business trips at the weekend, separate calculations will be undertaken for each of the journey purposes In SRTM3, all the employers business calculations are carried out separately from the consumer calculations so there will be no difficulty in ensuring that the correct levels of employer s business trips are included. Appropriate Demand Totals 3.17 The correct demand for each journey purpose will be estimated by: Applying journey purpose correction factors derived from TEMPRO weekday time period trip-ends and TEMPRO weekend trip ends, and Controlling the weekend demand (summed over the journey purposes) to match Report A5b: Off-Peak and Weekend Benefits 6

8 Automatic Traffic Count data for cars, or Electronic Ticket Machine data for public transport Neither of the data sources can directly yield a control total for the demand factoring process. In both cases, they must be used to calculate growth factors that apply to the total demand summed across all journey purposes. Applying these factors to the weekday inter-peak or offpeak demand matrices (summed over journey purpose) will yield the appropriate control total Thus, the process will first adjust for the differences in journey purpose split and second control to the expected total demand. The control will apply the same correction factor to each journey purpose For some tours, one leg will be in the relevant time period and the other outside it. We have routines in place for converting from tours to trips and then back to tours to maintain consistency. Report A5b: Off-Peak and Weekend Benefits 7

York Scarborough Bridge Economic Appraisal Update Technical Note

York Scarborough Bridge Economic Appraisal Update Technical Note Specification No. 1 Client name West Yorkshire Combined Authority Client reference M088 Discipline Transportation Project name CCAG2 Economics