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The Ability of Public Transport to Cope withTarget Passenger Increases: Final Report

4. ANALYSIS OF BUS CAPACITY UTILISATION

4.1 Introduction

4.1.1 This section focuses upon the current utilisation of bus capacity in the four study cities. It reports firstly, in Sections 4.2 to 4.5, on the analysis of the bus occupancy surveys that have been undertaken, revealing the extent to which existing capacity is utilised in each city.

4.1.2 Section 4.6 then presents, in aggregate form to protect commercial confidences, the recent trends in the bus service supply and demand across the four dominant operators. This is supplemented in Section 4.7 by a detailed analysis of changing bus service provision by Lothian Buses in Edinburgh, using publicly available timetables for the period since 1994.

4.2 Current Bus Capacity Utilisation in Each of the Four Study Cities

4.2.1 Prior to the presentation of the survey findings, it should be restated that this analysis is based upon single day observations at each survey location and, as such, provides only a snapshot of bus capacity utilisation. In addition, although the sample survey locations were selected on information provided by operators and local authorities as being representative of travel generally in the city areas there will - as with all samples - be some sampling error. The methodology adopted for the surveys is outlined in Section 3.2 above

Morning Peak Analysis

4.2.2 Table 4.1 summarises the percentage bus occupancy by surveyed cordon point during the morning peak period (i.e. from 0800 to 0900). This is shown in terms of seating capacity alone, followed by total bus occupancy, which incorporates the permitted number of standing passengers. Although these values are estimates for the full cordon they are based on observed data which have been related to the actual seated/standing capacities for the surveyed buses. From the survey results, it can be seen that overall there was an 82% seat utilisation where Edinburgh, Glasgow and Aberdeen were observed to have similar occupancy levels of between 84% and 87% of seated capacity. At 59%, seat capacity utilisation in Dundee was observed to be lower.

Table 4.1: Morning Peak Bus Occupancy at Surveyed Cordon Points

Inter-Peak Analysis

4.2.3 Similarly Table 4.2 summarises the inter-peak survey (i.e. from 1000 to 1200) and shows an overall seated capacity of 46% where Edinburgh, Glasgow and Dundee were observed to have similar occupancy levels of between 39% and 43% of seated capacity. Aberdeen was busier at 68%.

Table 4.2: Inter-Peak Bus Occupancy at Surveyed Cordon Points

Evening Peak Analysis

4.2.4 Table 4.3 highlights the results of the evening peak survey (i.e. from 1700 to 1800), with an overall seated capacity of 75% with Aberdeen having the highest observed utilisation of seated capacity (87%) and Edinburgh the lowest (69%). There is no obvious explanation why Edinburgh has the lowest seat utilisation; possible explanations include, sampling error, a broader peak (with respect to time) in Edinburgh and less demand for peak hour travel during the evening peak in Edinburgh. In terms of total bus capacity, there is considerably less variation, due to differences in fleet composition between operators, with a range from 52% in Aberdeen up to 61% in Glasgow.

Table 4.3: Evening Peak Bus Occupancy at Surveyed Cordon Points

4.3 Bus Overcrowding by Cordon Crossing Point

4.3.1 Tables 4.4 to 4.6 set out for the three survey periods the number of buses that were observed to be full. At crossing points not surveyed, a number of buses may have been running full and these cannot be reported here: The overcrowding statistics, therefore, present a picture of overcrowding for a sample of cordon crossing points - not for overcrowding on the full cordons.

Bus Overcrowding During the Morning Peak

4.3.2 In the context of this report, a full bus is defined as a bus observed to have no spare seated capacity. Overcrowding is defined in terms of full buses.

4.3.3 Table 4.4 shows overcrowding during the morning peak. At 14 stops,186 buses were observed to be running full. On average 6 standing passengers were observed on these buses and 13 passengers in total were "turned away" by the driver. In total, just under a third (30%) of buses were observed to be running full. Edinburgh and Glasgow show higher numbers of buses running full than Aberdeen and Glasgow. These data are shown in more detail in Appendix 2 Table A2.1

Table 4.4: Buses Observed as Full by City, Number of Buses and Passengers Standing or "Turned Away" for the Morning Peak (0800-0900)

Bus Overcrowding During the Inter-Peak Period

4.3.4 Table 4.5 shows the situation during the inter-peak period where, 31 buses were observed to be running full at a total of 10 stops. On average 4 standing passengers were observed on these full buses and 1 passenger in total was "turned away" by the driver. In total, 3% of buses observed were running full. These data are shown in more detail in Appendix 2 Table A2.2.

Table 4.5: Buses Observed as Full by Location, Number of Buses and Passengers Standing or "Turned Away" for the Inter-Peak Period (1000-1200)

Bus Overcrowding During the Evening Peak

4.3.5 Table 4.6 shows the situation during the evening peak period, where 91 buses were observed to be running full at a total of 13 stops. On average 5 standing passengers were observed on these buses and 7 passengers in total were "turned away" by the driver. Just over a fifth (21%) of observed buses were running full. These data are shown in more detail in Appendix 2 Table A2.3.

Table 4.6: Buses Observed as Full by Location, Number of Buses and Passengers Standing or "Turned Away" for the Evening Peak (1700-1800)

4.4 Bus Overcrowding by Route Number and Crossing Point

4.4.1 Detailed bus overcrowding information is provided in Appendix 2 Tables A2.4 - A2.8. These tables show the routes that were identified as being "overcrowded". The definition for overcrowded is at least two buses observed to be running full during the survey period.

Overcrowded Routes During the Morning Peak

4.4.2 During the morning peak there were 52 routes which were identified as being overcrowded ( see Appendix 2 Table A2.4). Of these 52 routes, over half (33) the services were operating with at least half the buses running full (shaded cells refer). In some instances more buses than timetabled were observed during the one hour survey. This may have been the result of congestion on the road network, which may also be a factor in the incidence of overcrowding, or due to the provision of non-timetabled relief services to cope with demand.

Overcrowded Routes During the Inter-Peak Period

4.4.3 During the inter-peak period there were 4 services which were identified as being overcrowded ( see Appendix 2 Table A2.5). Of these, no services were operating with at least half the buses running full.

Overcrowded Routes During the Evening Peak

4.4.4 During the evening peak there were 22 services which were identified as being overcrowded ( see Appendix 2 Table A2.6). Of these, 14 services were operating with at least half the buses running full (shaded cells refer). In some instances more buses than timetabled were observed during the one hour survey; this may have been the result of congestion on the road network, which may also be a factor in the incidence of overcrowding, or due to the provision of non-timetabled relief services to cope with demand.

4.5 Bus Overcrowding by Cordon Crossing Point and Time

4.5.1 Observations of overcrowded buses by ten minute interval during the morning peak period are set out in Appendix 2 Table A2.7. The greatest mismatch where demand exceeds supply was observed during the half hour period from 0820 to 0850.

4.5.2 Observations of overcrowded buses by ten minute interval during the evening peak period are set out in Appendix 2 Table A2.8. A clear peak in the number of full buses was observed during the middle of the period (1720-1740) with the later part of the hour more likely to have buses running full than the earlier part. This was in contrast to the flatter more sustained peak observed during the morning peak. Care needs to be exercised in drawing conclusions from these data - they comprise a sample of bus routes taken only on one day. Nevertheless, they may be viewed as indicative of quantitative differences between morning and evening peak bus supply and demand in general.

4.6 Trends in Bus Service Supply and Demand (Main Bus Operators)

4.6.1 In order to analyse the recent trends in the supply and usage of bus services in the study cities, data on fleet size, seating capacity provided, mileage operated and passengers carried annually over the period 1997/98 to 2001/02 were obtained from the principal bus operator in each of the four main cities. This section deals primarily with the quantitative elements of the analysis, with the findings of the detailed discussions with bus operators being presented later ( see Chapter 9).

4.6.2 To protect the commercial confidentiality of the four main bus operators, the data have been presented in aggregate form without making reference to individual operators' statistics. Table 4.7 sets out the annual percentage changes over the period 1997-2002, with a summary of changes over the complete five year period also shown. In terms of passengers carried, the trend appears to be similar to that shown in Figure 2.2 and with a continued increase in patronage in 2001/02. In contrast, the mileage operated by these big four bus operators has not increased in line with that shown for local bus services in Figure 2.1. The trends are discussed below and, in the light of the bus company discussions regarding targets, in Chapter 9.

Table 4.7 Percentage Changes in Bus Supply and Demand (1997-2002)

Changes in Supply

4.6.3 Two main trends are apparent from these figures. Firstly, there has been a big increase in the utilisation of the bus fleet. Approximately the same total mileage is being operated by a fleet which has been reduced by 15%. In fact, mileage has actually increased in three of the four operations, two only marginally and one significantly. Significant fleet reductions have taken place in three of the four operations but there has been a marginal increase in the other. The change in fleet size can perhaps be attributed to a reduction in school-related work and other subsidised services, both of which are now increasingly provided by smaller independent operators. In addition there has been a reduction in direct competition with the consequential withdrawal of directly competitive services which has improved overall fleet utilisation.

4.6.4 The second trend can be seen by the even greater reduction of seating capacity compared with fleet numbers. A 15% reduction in fleet is matched by a 28% reduction in seating capacity. This overall percentage hides a greater disparity, whereby one operator has marginally increased seating capacity which means that the reduction in seating capacity by the other three operators averages 35%. This reflects the trend towards low-floor single deck vehicles instead of double deckers. The reduction in seating capacity does not necessarily result in a proportional reduction in overall carrying capacity, as there has been an increase in standing capacity.

Changes in Demand

4.6.5 The overall figures (in Table 4.7) show no change in demand (measured by passengers carried) between 1997 and 2002 associated with the extremely small reduction in mileage operated. This overall trend however, masks a considerable disparity between different operators.

4.6.6 For two out of the four operators, there has been a steady but gentle decline in demand over the whole period. In a third area, there was a fairly steep decline between 1997 and 1999 but subsequently growth has re-emerged; so far this is not enough to offset the previous decline. In the fourth area growth has continued throughout the period to the extent that passenger carryings in 2002 are 16.5% greater than in 1997. The growth experienced by these latter two operators has been sufficient to outweigh the continued decline in the other areas so that the overall figures for the period 1999 to 2001 show a growth of about 1 to 2% per year, followed by 5% in the most recent year.

4.6.7 Anecdotal evidence which is put forward to explain this apparent change in the long term decline in bus usage includes such factors as:

• inner city regeneration - the redevelopment of older industrial areas on the periphery of the city centre has the benefit of stimulating demand on an already existing bus service network and infrastructure. This is more beneficial to bus operators compared with greenfield development which requires operators to expand their service provision in the hope of generating new demand. Furthermore greenfield development will generally provide a more car friendly environment in terms of greater parking facility and easier access to the main road network.
• greater night time usage - the expansion of night time entertainment with more pubs and clubs open for longer hours has stimulated demand for night time services. Although this requires operators to expand services this is obviously at a time when resources are more readily available.

4.6.8 City centre parking restrictions and congestion were not mentioned specifically by operators. This is perhaps because these factors have been present for a longer period than the past five years and buses generally are affected by the overall traffic congestion - see Chapter 9 for further discussion of these factors, together with additional commentary on bus capacity utilisation and the likely consequences for meeting the targets.

4.7 Detailed Case Study: Lothian Buses plc (Edinburgh)

4.7.1 To supplement the broad analysis of the trends in the four principal urban bus operators, a detailed investigation of capacity provided by one of these operators in Scotland, Lothian Buses (formerly Lothian Region Transport), has been carried out. Lothian Buses is the main bus operator in Edinburgh.

4.7.2 This analysis has been based upon the published service timetables between 1994 and 2002. Based on the available timetables, the analysis has considered four points in time, these being the spring of each of 1994, 1997, 2000 and 2002. In common with much of this study, most of the capacity analysis has focused upon the changes in provision to/from the city centre, since this is where capacity tends to be more of a premium. Some 16 cordon locations around the city centre were studied, these being consistent with the capacity surveys conducted for this study. Some further analysis of service provision to major trip generators elsewhere in Edinburgh has also been carried out to give the wider perspective.

4.7.3 Changes in three different measures of capacity provision have been analysed, for each of four different weekday time periods (these being: 0800-0900; 1100-1200; 1700-1800; and 2100-2200). The capacity measures were as follows:

• number of services scheduled per hour
• number of seats provided per hour
• total capacity (i.e. seats plus standing spaces) provided per hour

4.7.4 Services in the inward direction (either crossing the cordon or arriving at the other trip generators) were analysed in the first two time periods, and in the outward direction for the latter two periods. Seats and capacity provided were calculated by assuming that all buses on the route conformed to the "normal" type for that route. In practice, most routes are almost exclusively operated by one single bus type. Six different bus types were identified for capacity calculation purposes and minor capacity variations within these types were averaged based on the bus fleet composition.

4.7.5 A summary of the findings for the city centre cordon is shown in Table 4.8.

Table 4.8 Changes in Lothian Buses Capacity Provision to/from Edinburgh City Centre (1994 - 2002)

4.7.6 It was established from the bus capacity analysis earlier in this chapter that, as is typical with public transport operations, it is in the morning peak that capacity is nearest to being fully-utilised. Analysis of the morning peak reveals a mixed picture over the entire 1994 to 2002 period, with an 8% increase in the number of services entering the city centre and a 5% increase in total capacity provided, but a 1% decrease in the number of seats available. This reflects the trends identified earlier, these being a switch to smaller vehicles, predominantly single deckers instead of double deckers, and the introduction of low-floor buses that have fewer seats but a greater provision for standing passengers. The absolute number of services operated in the peak is likely to be less important than the capacity provided by these services, since if sufficient aggregate capacity is not provided, the service frequencies are largely irrelevant.

4.7.7 This analysis of the full eight years disguises the fact that there was generally decline in capacity provided in the early years, which has been followed by increases in all three measures since 2000. During the second time period, the senior management of the company changed and the network was revised in March 2000. Therefore the latter time period alone is probably the most appropriate reflection of the company in its present form.

4.7.8 In the evening peak, a similar trend is evident, though with stability in the number of seats provided since 2000 rather than the slight increase in the morning peak. However, the same reversal can be seen in all three measures since the mid-1990s and total city centre capacity provided in 2002 was some 5% higher than in 1994 and 3% higher than in 2000.

4.7.9 For the inter-peak (1100-1200) and evening (2100-2200) periods, where absolute capacity is not an issue, it is the level of service provision in terms of number of buses that is likely to be most significant in attracting patronage. In both the inter-peak and evening periods, there has been an increase in the number of buses per hour in recent years. While this is largely beyond the scope of this study, since capacity is not at a premium at these times, it does have implications for meeting non-work public transport mode share targets since spare capacity at these times could absorb considerable patronage growth.

4.7.10 Summary tables for the six other trip generators outwith the city centre are provided in Appendix 3. While these are purely indicative and do not necessarily reflect city-wide changes, they do reveal that the recent increases in peak capacity to/from the city centre have occurred at the same time as dramatic increases to many of the developing trip generators. It is quite possible, and indeed likely, that there has been a reduction in capacity elsewhere within the city. However, the analysis does suggest that Lothian Buses has recently been adapting its service provision to the changing land uses and travel demands whilst still focusing on the core city centre market.

4.8 Summary

4.8.1 This chapter, together with Chapter 2, has presented the analysis of the existing supply and demand of bus services. Whilst not without its limitations, this provides an overview of the current peak bus capacity utilisation in the four study cities.

4.8.2 The analysis of bus capacity utilisation is based on a series of one-day "snapshot" surveys and the conclusions drawn should be regarded as indicative rather than precise measurements of bus use. For Edinburgh and Glasgow, the morning peak is observed to have less spare capacity (13% and 16% respectively) than at other times of the day. In Aberdeen the morning and evening spare capacities are observed to be very similar with spare capacity in the range 13-14%. For Dundee the evening peak was observed to have less spare capacity (27%) than the morning peak. There is, therefore, existing spare capacity during the busiest periods.

4.8.3 Overcrowding is, however, clearly an indication of an inability to cope and there is evidence that a number of routes in each of the four cities do encounter problems of overcrowding. The reasons for this may include bunching caused by traffic congestion and mismatches in bus operation between supply and demand. It is not possible from this survey to identify the particular reasons why there should be overcrowding on particular routes. More overcrowding is observed during the morning peak. During both morning and evening peaks a number of bus routes where at least half the number of buses operating the route were observed to be running full - this might suggest a mismatch in demand and supply rather than random overcrowding caused by congestion and bunching.

4.8.4 In addition to the analysis of the bus surveys, this chapter has identified the major trends in supply and demand in the four main city bus operators, thus strengthening the base data for the study. This revealed that there has been a big increase in the utilisation of the bus fleet between 1997/98 and 2001/02, with approximately the same total mileage being operated by a fleet which has been reduced by 15%. Further, this 15% reduction in fleet has been matched by a 28% reduction in seating capacity. The reduction in seating capacity does not necessarily result in a proportional reduction in overall carrying capacity, as there has been an increase in standing capacity. The analysis has showed no change in demand (measured by passengers carried) between 1997/98 and 2001/02 associated with the extremely small reduction in mileage operated, although demand decreased in the first two years and has increased in each of the latter three years. This overall trend however, masks a considerable disparity between different operators.

4.8.5 Finally, a more detailed analysis of the changing nature of Lothian Buses' network and timetabling was presented. This analysis suggested that Lothian Buses has recently been adapting its service provision to the changing land uses and travel demands whilst still focusing on increasing capacity for the core city centre market.

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