Telematics technologies certainly have the potential to achieve this objective: they enable data collection concerning conditions across whole transport and traffic networks, they generate information from this data, and can transfer it to operators and users, keeping them constantly informed. This can allow the users to decide whether to make a journey, which is the most convenient means of transport and, which is the best route to reach the destination (in other words, it allows the demand to adapt to the current supply). At the same time, it makes it possible for transport operators to know the real situation of the transport and traffic network, predict its evolution and, consequently, determine the most appropriate management strategy (adapting the supply to the demand).
The extensive evaluation activity performed by QUARTET PLUS1 aimed to verify quantitatively this principle. An effort was also made to provide answers to certain fundamental questions concerning the operational potential, in the short and long term, of telematics applications under the following scenarios:
In this article, a synthesis of the experimental results obtained from the demonstration programmes carried out as part of QUARTET PLUS is presented, and an attempt is made to provide some initial elements on which to base replies to the questions posed above.
In evaluating the benefits of private traffic, tests were carried out with "floating cars" driving along selected routes ranging from 4 to 6 kilometres in length and compared with travel times recorded for public transport vehicles taking into account whole service lines. Efforts were made to ensure homogeneous traffic conditions for the different scenarios and to provide a sufficient sample to give over 95 percent confidence in the results. Results showed that an increase of about 17 percent in the average speed of private vehicles along the artery at peak time was measured in two of the QUARTET PLUS sites (Toulouse and Turin).
At the same time and in the same urban areas, attention was given to improving public transport (by giving priority to public vehicles). This was one of the most tested applications. Improving the quality and efficiency of public transport is generally felt to be one important factor that will attract more travellers to public transport. Gains in travel time, ranging from the 5-10 percent category and the 14-15 percent category were observed in Toulouse, Turin and Gothenburg, depending on the technology used.
The gains measured demonstrate that important benefits for users (both those travelling with private cars or public transport) are achieved through telematics systems providing better and coordinated control without affecting demand.
Parallel control trials were also implemented to evaluate whether giving priority to public transport negatively affects the efficiency of the traffic network for private vehicles. Resulting comparisons made of travel times for scenarios with and without public transport priority showed differences as low as 1 percent - not statistically relevant for flows crossing the priority public transport routes.
Direct benefits to the public transport operator from such an increase in average speed (and the reduction in the number of vehicles necessary for the same service) were calculated. In one example, the pay-back period for whole investment would be just over two and a half years. Under the same scenario, if the passenger time saved were translated into money terms, the investment (which, as we have seen, also benefits private traffic), would pay for itself in just a few months (to be exact, 131 days).
As the effect for private traffic was a reduction in waiting time at traffic lights and greater efficiency in travelling conditions, this also meant a decrease in exhaust emissions and fuel consumption. As an example, a reduction of around 5-6 percent in carbon monoxide emissions was estimated at different sites for one system.
It can be confirmed therefore that optimised telematics management produces quantitatively significant benefits. But the tests show also that, with the appropriate control strategies, the benefits are sufficiently high to provide economic justification to the investment involved. Even taking into account the public transport operator alone, the pay-back period is only a few years. Finally, these large-scale experiments have confirmed that the advantage enjoyed by public transport is not at the expense of private traffic. With the correct application of telematics, there are advantages to be enjoyed by all.
A series of tests (Origin and Destination experiments) were carried out to measure all the components of the travel time for a sample of trips between certain Origin and Destination points, both for private traffic and public transport. For this test, use was made of "floating vehicles" and passengers who had to make journeys in different parts of the city on different days, between origins and destinations extracted at random.
Compared scenarios were: i) those in which the system was not operated and where travellers chose the best route for reaching their destination according to their own knowledge and with the support of a map of the city, and; ii) those in which all the functions of the telematics system were activated and travellers followed the best route recommended by the trip planning function (pre-trip information), and then followed the indications provided by the VMS panels (Variable Message Signs for on-trip information). In other words O/D experiments aimed to assess the benefits due to the integrated effect of controlled management and information given to travellers.
All the necessary precautions were taken to ensure statistically significant results were obtained. Different areas of the city were chosen with different system penetration levels. The sample sizes were chosen to ensure 95 percent confidence in the results.
Benefits varied according to the O/D pair surveyed. They were normally high and tended to result during peak periods. This phenomenon could be explained by the actual lack of real-time information, which was important in peak hours when cities were affected by unpredictable congestions.
Since the benefit depended on the penetration level of the system equipment along the surveyed routes, a detailed analysis was performed by extrapolating the expected impact in a fully controlled network scenario.
In terms of tangible benefits to users, the application of large scale integrated management (control, routing, information) showed a reduction in average travel time as high as 20 percent. Additional trials showed that this benefit rises up to 21.6 percent if time searching for a parking place and the time to reach the final destination on foot is considered, (since these times are reduced by the detailed real time information given by the system). The effect of the system can be even greater, demonstrating the importance of information), if only travellers who are unfamiliar with the city are only considered.
It was also demonstrated that the reduction of pollutant emissions results from the routing strategy as an additional effect to the control system only. Local effects on emission reductions are as high as 18 percent (of which, 12 percent are due to the environmental routing, 6 percent to better traffic control) while global effects to the order of 7-8 percent were calculated (1.5 percent due to environmental routing, 6 percent due to better control).
For the same scenarios trials were also performed for assessing the impact of the systems on travellers using public transport. For this purpose a suitably large group of "test" travellers travelled from given origins to assigned destinations using public transport. While in the base scenario, they chose the best route according to their experience and knowledge, during the "system-on" scenario, they followed the optimal route recommended by the dynamic route planners, i.e. the best route according to current and predicted travel times on the network arcs.
Also in this case collected data were processed in order to extrapolate the impact in a scenario where the system controls the entire transportation network. Different methods were used to confirm the results, which at 100 percent penetration, has thus been fixed at 19 percent travel time reduction by using public transport.
All results mentioned in this section are the results of extensive field trials performed at the different QUARTET Plus sites and were also confirmed directly by all users that were approached by the project at all sites by means of user groups, user fora and user panels.
Telematics' Role in Modifying Demand
After verifying the effectiveness of telematics for the same levels of demand, the question was posed as to whether telematics can also help, when required, to transfer demand from private to public transport or achieve other positive modifications, such as the reduction of unnecessary trips, or the movement of trips to non peak periods.
These possible effects were also examined. It is, in fact, extremely difficult to verify in a statistically significant way any switch in demand induced by telematics systems such as those adopted in Quartet Plus. Even when applied on a large scale, they do not influence the whole population, and produce effects which may, in the short term, be easily masked by other factors, such as economic issues. It was therefore necessary to make an indirect evaluation from an analysis of user preferences, the reactions to variations introduced in the system, and user perceptions of the service quality. For this purpose, reference was made to the responses and behaviour of the user panels, and to specific surveys designed to assess user reactions.
Open surveys were used to evaluate opinion concerning the impact of two technologies designed to improve the perceived quality of service through information provision in Turin: panels at bus/tram stops, and on-board information. The former provided users with forecasts of the arrival times of vehicles, the latter informed passengers, by voice and visually, of the next stop. In both cases the survey results were very positive. Responses confirm that the majority of users (75 percent) found the telematics systems useful and approved of the cost to the public authority. They also indicated that a high percentage would be willing to pay individually for a public transport information service.
In Gothenburg, a questionnaire distributed to 400 users indicated high appreciation of the quality of the information service for public transport (with an average score of 8/10). 85 percent considered the service useful and "worth spending public money for." Users also stated that the information provided helped to reduce stress, allow better time management and hence a more efficient journey.
At the Torino site, an independent market research company produced a report on the analysis of the user panels and provided further interesting statistical data concerning actual travel behaviour. In the Turin trials, between January and October, the percentage of recorded trips made by panel members on public transport increased by 3 percent.
In Gothenburg, a similar modal shift (2 percent) to public transport was claimed by users in interviews. This would seem to indicate the increased attraction in using public transport, which could be due to the effects of the information system, or possibly the 'promotion' of the system to those surveyed. The result is certainly in line with the users' general perception of a clear improvement in public transport, but obviously needs to be confirmed by longer term behaviour. The public's appreciation of the information systems was, in general, high and the average user stated that he/she would use public transport more often if precise real time information were available (even upon payment). Users demonstrated also high appreciation and use of the corresponding Internet services. They were tested at various sites, and with very positive results. In general the number of hits are impressive.
In the cities of Athens and Gothenburg, the Internet information services had considerable success. In Athens, practically all users (97 percent) reported that the information was easily understood and also useful as respondents claimed a high awareness of the pollution issue. 67 percent claimed they would often follow an alternative route proposed on the basis of environmental criteria, rather than pass through the centre of Athens. Many of Gothenburg's users stated that the information made it possible to reduce waiting time (by influencing the time of departure) and helped to organise a more efficient trip. A small survey performed in Stuttgart showed that 17 percent of respondents claimed they would be willing to switch from using their private vehicles to using the "park and ride" service as a result of the information they obtained via Internet; another 8 percent claimed they would switch from their private cars to public transport.
From the point of view of pollutant emissions, it has to be noted that a modal shift toward public transport determines a reduction of pollutant emissions of at least the same percentage. This means that where a shift of 3 percent in favour of public transport is measured, a local reduction of up to 21 percent can be achieved.
In conclusion, neither the user surveys nor the panel, although positive, can provide definite quantitative data in the assumption that telematics contributes to a switch in demand from private to public transport. They do however show that it is possible to modify the public's perception of service quality and to increase the convenience of its use (as well as its performance). Both are conditions which make changes in demand possible.
While the MATTISSE case-study gave very promising forecasts for revenues from such services, on the contrary, the three sites, which during Quartet and/or Quartet Plus were testing individual route guidance systems (the traditional, first candidate for such traffic management services) all decided not to proceed with such systems (Stuttgart, Athens, Torino).
Some comparatively long-term scenarios were produced for large-scale telematics implementation. Even using conservative estimates of impacts, they show that transport telematics, in a proper scenario, can produce, at affordable cost, better efficiency, increased safety and reduced emissions and, in general, very high benefits for operators.
The socio-economic analyses of Integrated Telematics Scenarios demonstrate that telematics systems consisting of traffic information and control telematics applications can, by a reasonable integration of measures in the private and public transport sector, lead to an improvement of traffic operation and environmental impacts in both transport systems in metropolitan areas. For all scenarios, benefits exceed costs.
For the Stuttgart and Gothenburg Greater Areas, long term socio-economic studies were carried out, both comparing a basic scenario consisting of conventional traffic information and control systems with two Integrated Telematics Applications Scenarios; one more oriented toward public transport, the other more oriented to private transport. The benefit-cost ratio resulted greater than 1 for both scenarios in the Stuttgart Greater Area (Mobin), with the public transport scenario showing the more favourable ratio of 3.3 when compared with 1.7 for the private transport scenario. These results correspond with those of the Gothenburg project (Tosca), which gives a clear preference to the public transport scenario. The analysis of a virtual Quartet Plus City Scenario, consisting of all telematics applications validated in the six cities resulted in a benefit-cost ratio of 3:0 and 2:0 respectively.
All the impacts considered in the socio-economic assessment appear very conservative with respect to the results of the field trials. Indeed, the previous sections have considered the possible benefits (in terms of travel time saved) to be as high as 20 percent, which were then translated into emission benefits (network wide) to be as high as 10 percent.
On the other hand, it must be considered that:
Moreover the above results assume fixed demand; in the long term, this hypothesis cannot be true, since the demand will react to the new network capacity (an average saving of 20 percent in on-board time in congested situations implies an equivalent increase in available network capacity). Thus, the conclusion of the socio-economic assessment indicates that the "Public Transport" oriented scenarios are only worth consideration. The new capacity obtained through transport telematics must be used to accommodate a better Public Transport system. From this point of view, the socio-economic assessment and the field trials give the same answer.
For the Torino site, the economic benefits of traffic-light priority were calculated, both for users and the public transport system. The analysis took into account the real situation (traffic, demand, operations) of a selected service line and of the corresponding arterials, considering all costs involved in the installation of the system in terms of installation, tuning, maintenance and communication. Benefits were considered for the users of public transport and private mobility in terms of travel time savings, and for the public transport company in terms of using less employees and vehicles.
Based on the above premises, the balance equation of the investment gives a theoretical return time on the investment of 131 days! If the benefits for the individual users (time savings) are not considered, only the economic benefits for the public transport company due to the reduced number of vehicle shifts and driver shifts would remain. In that case, the investment return time would be 1,296 days. That is, in approximately three and a half years the investment would be repaid. If, on the other hand, only the (estimated) quota corresponding to the considered service line is considered, the investment return would occur in approximately two and a half years (922 days).
Also, for the French sites of Toulouse and Pau, the socio-economic evaluation of possible benefits ensuing from an extension of the bus-priority systems was performed. First year rates of return of 20.7 percent and 19.4 percent respectively were extrapolated. Improvements to the system would permit the fleet to be reduced by one bus would take the rate of return to 22 percent.
Quartet Plus Project, Deliverable D04.1 Issue 2 "Validation of User Behavioural Changes due to Multimodal Traffic Information and Related Impacts on the Transport System", Feb. 1998.
Quartet Plus Project, Deliverable D05.1 Issue 2 "Validation of IRTE Supported Public Transport Management", Feb. 1998.
Quartet Plus Project, Deliverable D07.3 "IRTE Evaluation in Six Sites: Results of the European Approach", March 1998.