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41 one would expect to see that an ATCS performance in peak Costs of communications and training periods is not so beneficial. However, the survey reported that Extensive experience necessary to get most benefits. 37% of the agencies found ATCSs to be the most effective during peak periods. Twenty-three percent of the agencies found the highest ATCS benefits during the off-peak periods, PUBLIC PERCEPTION whereas 23% of the ATCS users found ATCSs to be the most Installation of an ATCS does not readily provide observable beneficial at the shoulders of peak traffic periods. Another benefits to the traveling public. If the previous conventional 19% selected combinations of the aforementioned options. traffic signal control was maintained properly it may be diffi- These results are slightly counterintuitive when one considers cult for an ATCS to achieve benefits higher than 10% to 15% findings about weak benefits of ATCSs in oversaturation. for any of the performance measures. Indeed, a 10% to 15% Most likely, oversaturated conditions experienced by the reduction in delays and stops is something that an everyday interviewed agencies do not extend over the entire length of traveler may not notice easily. Despite this some agencies the peak periods. Therefore, because oversaturated conditions are shorter than peak periods, ATCSs are considered to be decide to conduct a public education campaign in which they beneficial during those parts of peak periods when there is no attempt to familiarize the traveling population with the new oversaturation. system and its working principles. ATCS operations can degrade over time owing to changes One of the primary reasons for conducting public education in operational traffic conditions and the inability of some of campaigns is that agencies implementing ATCSs would like to the ATCS parameters to self-adjust to those changes. Some of justify, to the travelers, reasons for potential changes in traffic the ATCS' user manuals document parameters that are sub- signal operations and thus reduce the potential number of com- ject to the "ageing" process. It appears that most of the ATCSs plaint calls. Travelers who are convinced that, overall, the new can cope well with degradation in their performance. Most of system provides more benefits than the old one may not com- the ATCS users (79%) find that their ATCSs have achieved a plain as much about certain operations that may become worse sustained level of performance since the initial installations; through ATCS deployment. However, in spite of the good another 21% believe the opposite. One could note that only a intentions, the decision to conduct an education campaign few of the ATCS users have done multiple evaluation stud- may bring more problems than benefits. Actually, at times the ies during the course of their ATCS deployment. number of complaint calls increases after installation of a new ATCS not because the performance of the new system is Multiple evaluation studies can be used to objectively doc- worse, but because travelers subjectively believe that things ument that the level of ATCS performance has been sustained. have worsened with the installation of the new system. For this The following list shows some examples of ATCS' users' or similar reasons many ATCS agencies do not conduct pub- responses on specific benefits and costs observed in operations lic education campaigns. Results from our survey show that of their ATCS deployments. approximately 58% of ATCS users never launched an educa- tion campaign about deployment of their system. Of those · Advantages agencies that conducted public education campaigns there are Fuel consumption benefits none that reported that the campaign was effective. Sixteen City council sees the increase in efficiency percent of the interviewed agencies found that their campaigns Thirty-three intersections resulted in more than were somewhat effective and another 25% reported that $1 million in fuel reduction the campaign was either neutral (23%) or slightly ineffective. Just the normal obvious benefits with adaptive control Interestingly, no agency reported that the campaign was very Reduction in air pollution ineffective. One might also note that deployment of an ATCS $583,996/$542,511 one-year ratio of benefits/costs represents an action (by an ATCS agency) that is done to ease Engineer less exposed in field traffic congestion and improve arterial traffic operations. As Decreased time to develop signal timings such, this action has some political weight, and it is important Public transport priority and emergency vehicle that its promotional benefits not be underestimated. priority Lower cycle lengths--better pedestrian response Surveying travelers to investigate the impact of newly Accommodates roadwork and special events. installed ATCSs on traffic performance is not a common way · Negatives to evaluate the quality of an ATCS. However, some agencies Cost of software maintenance too high for the city perform such a survey expecting to catch potential ATCS Save in costs of conducting traffic counts--system benefits that might be missed by common traffic engineering does it for you studies (e.g., travel time, stop, and delay studies). Of all inter- Extremely expensive to maintain viewed ATCS users only 33% conducted any public percep- Requires substantial manpower to maintain system tion survey to catch benefits of ATCS deployment. Results of Additional overhead for maintenance/licensing those surveys were reported in Table 14.