Urban Route Research Articles

Economic Benefits Assessment of Accelerated Pavement Testing Research in California

A cost–benefit analysis method for determining the economic benefits of heavy vehicle simulator testing was evaluated. The University of California and its research partners began conducting accelerated pavement testing in 1994 on behalf of the California Department of Transportation. The authors present the findings of a pilot project intended to define a method suitable for measuring the direct economic benefits of heavy vehicle simulator testing in California. The chosen method was based on a cost–benefit analysis initially developed in Australia and later enhanced and applied in South Africa to determine economic benefits of their respective accelerated pavement testing programs. Results of a case study applying the Australian–South African method to heavy vehicle simulator tests conducted in California are presented. The case study evaluated benefits (in cost savings) from heavy vehicle simulator tests performed to validate innovative pavement mixes and designs proposed for the rehabilitation of a high-traffic urban Interstate route in the Los Angeles, California, area. Although local conditions in these countries differed significantly, the method was successfully applied and consistently showed positive results, presented as discounted net present value and benefit–cost ratio. Sensitivity analysis is recommended to determine a range of savings instead of a single benefit–cost ratio.

The Journey to Work: 25 Years on the Jamaicaway

More than 600 observations were recorded for the author's home-to-work trip for the same route from Boston to Cambridge, Mass., over the period 1980 to 2004. With this data, it is possible to graph the pattern of travel times and travel time reliability as a function of departure times during the morning rush hour. The image of rush hour performance that emerges from this study is more complex than what is often used in network models or abstract economic analysis. For example, as rush hour progresses, variability increases even though expected travel times start to decline. There may also be lulls in rush hour, i.e. intervals of 10-15 minutes when expected trip times and reliability temporarily improve. This type of performance cannot realistically be modeled as a linear function of traffic volume, nor can it be approximated using a steady state queuing analysis. It will be far better to view rush hour performance as a steady state cyclical queuing phenomenon: every day may start afresh, but expected conditions on next Tuesday at 8:30 am are likely to be similar to conditions last Tuesday at that time.Over the 25-year period, there was surprisingly little change in rush hour performance on this congested urban route. Average travel times were mostly in the range of 25-27 minutes with a standard deviation of three to four minutes. There was some spreading of the peak, especially during periods involving major construction, but performance in the most recent period was actually equivalent to performance in the 1980s despite an increase of about 10% in traffic volume. Variability in trip times is mostly related to variability in the delays associated with the most congested

A case study of exposure to ultrafine particles from secondhand tobacco smoke in an automobile

Secondhand tobacco smoke (SHS) in enclosed spaces is a major source of potentially harmful airborne particles. To quantify exposure to ultrafine particles (UFP) because of SHS and to investigate the interaction between pollutants from SHS and vehicular emissions, number concentration and size distribution of UFP and other air pollutants (CO, CO(2) , and PM(2.5)) were measured inside a moving vehicle under five different ventilation conditions. A major interstate freeway with a speed limit of 60 mph and an urban roadway with a speed limit of 30 mph were selected to represent typical urban routes. In a typical 30-min commute on urban roadways, the SHS of one cigarette exposed passengers to approximately 10 times the UFP and 120 times the PM(2.5) of ambient air. The most effective solution to protect passengers from SHS exposure is to abstain from smoking in the vehicle. Opening a window is an effective method for decreasing pollutant exposures on most urban roadways. However, under road conditions with high UFP concentrations, such as tunnels or busy freeways with high proportion of heavy-duty diesel trucks (such as the 710 Freeway in Los Angeles, CA, USA), opening a window is not a viable method to reduce UFPs. Time budget studies show that Americans spend, on average, more than 60 min each day in enclosed vehicles. Smoking inside vehicles can expose the driver and other passengers to high levels of pollutants. Thus, an understanding of the variations and interactions of secondhand tobacco smoke (SHS) and vehicular emissions under realistic driving conditions is necessary. Results of this study indicated that high ventilation rates can effectively dilute ultrafine particles (UFP) inside moving vehicles on urban routes. However, driving with open windows and an increased air exchange rate (AER) are not recommended on tunnels and heavily travelled freeways.

Driving cycle for motorcycles in modern cities: case studies of Edinburgh and Delhi

Driving cycle is an essential requirement to evaluate the exhaust emissions of various types of vehicles on the chassis dynamometer test. This study presents a real world comparison of the driving cycles of Edinburgh motorcycles in two world cities; Edinburgh in Scotland and Delhi in India. The two driving cycles (EMDC & DMDC) driving cycle (EMDC) that were was developed through the analysis of experimental data. This data was collected from trips on a number of routes in each city. In Edinburgh, five different routes between the home addresses in the surrounding areas and place of work at Edinburgh Napier University in Edinburgh were selected. In Delhi data were collected in East Delhi (Geeta Calony) to Central Delhi (Raisena Road). The data collected data was divided into two categories of urban and rural roads in the case of Edinburgh while it was only the urban route in Delhi.. Forty four trips were made on the five designated routes in both urban and rural areas and 12 trips were made in Delhi. The aims of the study were to assess the various parameters (i.e. motorcycle speed, cruise, accelerations and decelerations and percentage time spent in idling) and their statistical validity over total trip lengths for producing a real world EMDC in each of the two cities. The results show that EMDC in Edinburgh, the EMDC has a cycle length of 770 and 656 seconds for urban and rural trips, respectively, which was found more than ECE cycle length. Time spent in acceleration and deceleration modes were found to be significantly higher than any other driving cycle reported to date for motorcycles, reflecting a typical characteristic of the driving cycle in Edinburgh; this was presumably due to diverse driving conditions of motorcycles in the city. In Delhi on the other hand, the DMDC has a cycle length of 847.5 seconds for the urban trips, which higher than that of the EMDC length. The overall percentage time spent in acceleration in Delhi was higher than that of Edinburgh while the time spent in deceleration was lower in Delhi. The overall average speed in the case of Delhi was slightly higher than that of Edinburgh.

A Rough Set Model for Travel Time Prediction

AbstractTravel time prediction of urban networks was studied. Since urban travel times are stochastic and uncertain, a model for addressing urban travel time prediction by using transport information granular computing theory based on rough set was proposed. An urban route of Delft, the Netherlands, was selected as the test bed to test the proposed model. The results show that (1) feed with raw data, the model produces error of 35%; (2) with data pre-processing, the model improves performance significantly; (3) the classifications of condition and decision attributes significantly influence the accuracy. With the optimal setting of the ranges, the proposed model is able to describe traffic phenomena with physical meaning. Overall, the accuracy is acceptable.

Effects of e-map format and sub-windows on driving performance and glance behavior when using an in-vehicle navigation system

An on-road driving experiment was conducted to investigate the effects of e-map format and sub-windows on driving performance and glance behavior of navigation system users. Twenty-eight participants navigated an urban route using the navigation display with 2D or 3D e-maps and either with or without sub-windows. Driver navigation errors and visual glance data were gathered during the trials. The analytical results demonstrate no significant difference in driving performance between the 2D and 3D e-map conditions. However, use of a 3D e-map was associated with significantly more frequent glance behavior than the 2D display. Furthermore, subjects using the navigation display with a sub-window made significantly fewer navigation errors (50% less) compared to those using the navigation display without a sub-window. This investigation suggests that performance improves when using sub-windows. Finally, this study discusses wider implications in the design and use of navigation displays. Relevance to industry We found that the e-map format is related to driver glance behavior when using an in-vehicle navigation display. The sub-window also provides substantial influence on driving performance and glance behavior. The results of our study will assist in designing in-vehicle navigation systems and improving the performance of navigation e-maps for path-finding tasks.

Conversion of a commercial spark ignition engine to run on hydrogen: Performance comparison using hydrogen and gasoline

The modifications performed to convert the spark ignition gasoline-fueled internal combustion engine of a Volkswagen Polo 1.4 to run with hydrogen are described. The car is representative of small vehicles widely used for both city and interurban traffic. Main changes included the inlet manifold, gas injectors, oil radiator and the electronic management unit. Injection and ignition advance timing maps were developed for lean mixtures with values of the air to hydrogen equivalence ratio ( λ) between 1.6 and 3. The established engine control parameters allowed the safe operation of the hydrogen-fueled engine (H 2ICE) free of knock, backfire and pre-ignition as well with reasonably low NO x emissions. The H 2ICE reached best brake torque of 63 Nm at 3800 rpm and maximum brake power of 32 kW at 5000 rpm. In general, the brake thermal efficiency of the H 2ICE is greater than that of gasoline-fueled engine except for the H 2ICE working at very lean conditions ( λ = 2.5) and high speeds (above 4000 rpm). A significant effect of the spark advance on the NO x emissions has been found, specially for relatively rich mixtures ( λ < 2). Small changes of spark advance with respect to the optimum value for maximum brake torque give rise to an increase of pollutant emissions. It has been estimated that the hydrogen-fueled Volkswagen Polo could reach a maximum speed of 140 km/h with the adapted engine. Moreover, there is enough reserve of power for the vehicle moving on typical urban routes and routes with slopes up to 10%.

Reliability Analysis of Mechanical Systems With Bounded and Bathtub Shaped Intensity Function

This paper presents a new stochastic point process able to analyse the failure pattern of complex mechanical systems experiencing both early failures and degradation phenomena, and operating so long that the intensity function approaches a finite asymptote as the system age grows. We illustrate the characteristics of the proposed model. Then we give the maximum likelihood estimators of the model parameters, and some quantities of interest such as the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</i> -expected number of early failures, the time of minimum intensity, and the minimum intensity value. Inference on the number of failures that will occur in future time intervals is also provided. We applied the proposed model to real failure data from the powertrain system of two buses operating in urban routes in the city of Naples.

Fuel consumption estimation for kerbside municipal solid waste (MSW) collection activities

Fuel consumption during seven different daily activities of a garbage co-collection truck and a normal packer truck was estimated from the trucks' global positioning system (GPS) data and fuel consumption records. The co-collection and the normal garbage packer consumed approximately 1.8 L and 1.26 L of diesel per km, respectively, while travelling within the collection areas. Using these fuel rates and the GPS data, the results show that both types of trucks consumed more than 60% of daily total fuel while actually collecting waste on the route. The average daily fuel consumption was 2-4 times higher on rural routes compared to urban areas. Fuel consumption varied significantly depending on the housing density along the collection route. In addition, approximately 5-6 times as much fuel was required to collect a kilogram of waste on a rural route compared to an urban route. Potential methods of reducing fuel consumption were examined. Consistent use of optimal collection routes could potentially save an average of 7.5 L of fuel per truck per day. Reducing the loading time per stop was also studied, but the results suggest that this method does not have significant potential to reduce fuel consumption.

Effects of In-Car Support on Mental Workload and Driving Performance of Older Drivers

This study examined the extent to which driving performance of 10 older (70-88 years old) and 30 younger participants (30-50 years old) improves as a result of support by a driver assistance system. Various studies have indicated that advanced driver assistance systems (ADAS) may provide tailored assistance for older drivers and thereby improve their safe mobility. While drivers followed an urban route in a driving simulator, an ADAS provided them with prior knowledge on the next intersection. The system was evaluated in terms of effects on workload and safety performance. Messages informing drivers about the right-of-way regulation, obstructed view of an intersection, and safe gaps to join or cross traffic streams led to safer driving performance. A message regarding an unexpected one-way street led to fewer route errors. In general, effects were the same for all age groups. Workload was not reduced by the support system. The evaluated support system shows promising effects for all age groups. Longer evaluation periods are needed to determine long-term effects. The messages provided by the evaluated system are currently not provided by existing ADAS such as advanced cruise control and navigation systems, but they could possibly be added to them in the future.

Whole-body vibration exposure experienced by motorcycle riders – An evaluation according to ISO 2631-1 and ISO 2631-5 standards

Riders of twelve motorcycles, comprising 6 full-scale motorbikes and 6 motor-scooters, and 5 sedan vehicles, performed test runs on a 20.6 km paved road composed of 5 km, 5 km, and 10.6 km of rural, provincial and urban routes, respectively. Each test run of motorcycle was separately performed under speed limits of 55 km/h and 40 km/h. Tri-axial accelerations of whole-body vibration (WBV) were obtained by using a seat pad and a portable data logger, and the driver's view was videotaped with a portable media recorder. Root mean square ( RMS) acceleration, 8-h estimated vibration dose value ( VDV (8)) and 8-h estimated daily dose of static compression dose ( S ed ) were determined from the collected data in accordance with ISO 2631-1 and ISO 2631-5 standards. Experimental results indicate that the WBV values of the sedan vehicle drivers have low RMS, VDV (8) and S ed values ( RMS 0.27–0.32 m/s 2; VDV (8) 6.3–8.3 m/s 1.75; S ed 0.21–0.26 MPa). However, over 90% of the motorcycle riders had VDV (8) (mean 23.5 m/s 1.75) exceeding the upper boundary of health guidance caution zone (17 m/s 1.75) recommended by ISO 2631-1, or had S ed (mean 1.17 MPa) exceeding the value associated with a high probability of adverse health effects (0.8 MPa) recommended by ISO 2631-5. Over 50% of the motorcycle riders reached these boundary values for VDV and S e in less than 2 h. The WBV exposure levels of the full-scale motorbikes riders and motor-scooter riders were not significantly different. However, the RMS and VDV (8) values of motorcycle riders indicate significant roadway effect ( p < 0.001), while their S ed values indicate significant speed limit effect ( p < 0.05). This study concludes that the WBV exposure levels of common motorcycle riders are distinctively higher than those of sedans, even on a regular paved road. The impact on health of WBV exposure in motorcycle riders should be carefully addressed with reference to ISO 2631-1 and ISO 2631-5. Relevance to industry This study compares the predicted health risks of motorcycle riders according to ISO 2631-1 and ISO 2631-5 standards. Experimental data suggest that the vibration dose value of ISO 2631-1 and daily dose of equivalent static compression stress of ISO 2631-5 have roughly equivalent boundaries for probable health effects.

Drive-style emissions testing on the latest two Honda hybrid technologies

Abstract Introduction Hybrid technology is seen by many as a potential solution to reduce vehicle emissions in cities. However type approval tests of hybrid vehicles measure emission levels comparable to those of conventional cars in the same market segment. It has been argued that type approval tests do not represent the reality of emission in cities therefore, to quantify the real emission of hybrids and to compare them with those of conventional vehicles in the same conditions, an emission measurement campaign was organised. Acquisition campaign Three Honda cars, one conventional (the Civic 2.0) and two hybrids (the Civic IMA and the Civic Hybrid), equipped to collect emissions as well as the engine and vehicle working parameters were driven three times by twenty drivers on the same urban route. Drivers were asked to drive normally and not requested to do anything special but to scrupulously follow the given itinerary. Results Two main results were obtained: average and maximum emission levels for the three cars are quantified; the effects of the drivers on such levels assessed. The conventional car (with two people and 250 kg of measurement tools onboard) consumes an average of 12.6 l/100 km, its CO2 emissions range between 200 g/km and 300 g/km with an average of 260 g/km. CO emissions range between 0.25 g/km and 6.25 g/km (Euro IV limit is 1 g/km) with an average of 2 g/km. The most recent of the two tested hybrids consume in average 8.23 l/100 km and emits between 150 and 230 g/km of CO2 with an average of about 180 g/km; it emits virtually no CO in the majority of cases but can reach up to 1.8 g/km and average CO emissions are about 0.2 g/km. The hybrid performs always better than the conventional; in terms of CO2 and consumption it can have up to a 30% reduction and in terms of CO up to 90% reduction. Conclusions The wideness of the measured ranges depends mostly on the drivers. Women tend to consume and emit less than men. The reason for this is the different way they use the accelerator pedal; they push it less and keep it steadier. In other word the standard deviation of the accelerator position (or throttle) is lower. It is here shown how a correlation exist between the throttle standard deviation and the emissions which justify using such parameter as the indicator of drive-style.

Route-choice models reflecting the use of travel navigation information in a vehicle-based microscopic simulation system

To evaluate the impacts of traveller information through microscopic simulation, it is essential and critical to build route-choice models that are expected to correctly represent the use of traveller information by various categories of drivers. Urban commuters' route choices are usually based on the perceived delay between actual arrival time and preferred arrival time (indifference band of route delay). In this study, a fuzzy set is used to represent the effect of an indifference band of route delay on the tendency for a specific category of drivers to change routes. Fuzzy sets are used to describe the reactions of drivers to traveller information with respect to their tendency to change routes. This methodology shows potential to more realistically represent the effects of real-time information on route choice than can be accomplished using binary choice models.

Online Travel Time Estimation in Urban Areas Using the Occupancy of Long Loop Detectors

Roads in the Netherlands are often heavily congested. Real-time travel time information can be a valuable instrument to reduce the impact of increasing traffic demand on travel time with advantages for traffic participants as well as for the traffic network managers. For urban roads travel time estimation is a more complex problem than for freeways. In order to provide online, real-time and accurate travel times, in this paper a new estimation approach is developed based on measurements supplied by the (vehicle-dependent) traffic controllers. These measurements include the occupancy from the corresponding long loop, the flow from the short loop, and the green percentages. Based on these measurements the location and length of the queues is estimated. Moreover, the approach transforms the data in a way that the underlying reason(s) of congestion becomes apparent (in terms of bottleneck location), which can be very useful for, e.g., advanced traffic information systems or decision support systems. Compared with the approach based on license plate recognition cameras, which is used in the Netherlands in many locations, this approach is expected to be more accurate in heavily congested situations, since for license plate recognition vehicles have to pass the end of the route before the traveled time can be measured. The approach is tested with real traffic data for an urban route in the Netherlands. The test case presented in the paper shows that the use of the additional data from traffic controllers (occupancy, green percentage, waiting time of first vehicle in queue) is beneficial.

Study on Traffic Safety Improvement under a Model Project with Comprehensiveness and All-people Approaches in an Urban Route of Hanoi

Study on Traffic Safety Improvement under a Model Project with Comprehensiveness and All-people Approaches in an Urban Route of Hanoi

Comparison of GHG emissions from diesel, biodiesel and natural gas refuse trucks of the City of Madrid

The aim of this paper is to carry out a comparative study with regard to energy consumption and greenhouse gas emissions, in respect of two types of engines with three different fuels. The fuels analysed are diesel, biodiesel 30% (B30) and compressed natural gas (CNG). The engines tested were a spark ignition engine (Otto cycle) and two compression ignition engines (Diesel cycle), the first fed with CNG and the last two with B30 and diesel. What is new about this study is its scope of application concerning refuse collection services in the city of Madrid. The tests were carried out on refuse trucks of the FCC Company along actual urban routes in the city of Madrid. Also taken into account were the energy input and the greenhouse gases emitted for each of the paths taken by the fuels analysed, from resource recovery to delivery to the vehicle tank.

Efficiency comparison between FC and ice in real urban driving cycles

A deep experimental campaign on road carried out in an urban route had been allowed to acquire a huge database concerning the real operating conditions of several vehicle typologies, both conventional and innovative (hybrids). In this paper, using a different approach seen as the current one utilised in the type approval procedure, these experimental data will be the starting working base to accomplish a whole energy comparison between a PEMFC vehicle and a EURO 4 vehicle. The in-house model built in the University of Rome lab will be adapted and applied to an automotive load simulation based on measured driving acquisitions. A complete picture on the energy consumption and pollutant emission of the two vehicle typologies in their real use is provided. This encompasses also an examination of the fuel production, in order to extend the analysis to all the energy chain and perform a well-to-wheel study.

Definition of traffic scennaries, application on a practise case of the criteria followed by the guide of good practises for elaboration of strategic traffic noise maps in urban routes

Configuration of noisy environment in towns mostly depends upon the characterization of traffic noise in urban routes. Frequently there is a lack of information when it is a question of having data from the whole urban area. To solve this lack of information the above‐mentioned guide (WG‐AEN 002.2006) proposes some suppositions for this characterization which can turn out to be very general in practical applications. Through the presentation of these criteria applied to a practical case it can be seen the tools necessary to adjust real traffic characterization to the elaboration of noise maps and definition of an Action Plan. The analyzed variables are: AVT, % of heavy vehicles, time distribution and speed considering, for this last factor, the lacks shown by the interim method and the applicable supposes based upon the state of the art.

Design of a Hybrid Power Plant for City Buses

This paper presents a preliminary system design for a no-emission hybrid power plant for city buses working in a “dense grid” transportation network with short, regular stop spacing. The vehicle is driven by two electric motors powered by a hybrid unit composed of a fuel cell and flywheel energy storage system that takes into account the characteristics of urban routes. The advantages and disadvantages of flywheel technology on board a vehicle are examined and discussed and an in-depth study of the proposed hybrid architecture was performed by analyzing and measuring the main power components for a small sized city bus with a 15 passenger capacity.

Assessing the Potential of Predictive Control for Hybrid Vehicle Powertrains Using Stochastic Dynamic Programming

The potential for reduced fuel consumption of hybrid electric vehicles by the use of predictive powertrain control was assessed on measured-drive data from an urban route with varying topography. The assessment was done by evaluating the fuel consumption using three optimal controllers, each with a different level of information access to the driven route. The lowest information case represents that the vehicle knows that it is being driven in a certain environment, e.g., city driving, and that the controller has been optimized for that type of environment. The second highest information level represents a vehicle equipped with a GPS combined with a traffic-flow information system. In the highest information level, the future power demand is completely known to the control system, hence, the corresponding optimal controller results in the minimal attainable fuel consumption. This paper showed that good performance (1%-3% from the minimal attainable fuel consumption) can be achieved with the lowest information case, with a time-invariant controller that is optimized to the environment. The second highest information level results in less than 0.2% higher consumption than the minimal attainable on the studied route. This means that it is possible to design a predictive controller based on information supplied by the vehicle-navigation system and traffic-flow-information systems that can come very close to the minimal attainable fuel consumption. A novel algorithm that uses information supplied by the vehicle-navigation system was presented. The proposed algorithm results in a consumption only 0.3% from the minimal attainable consumption on the studied route