Automatic Traffic Counters Research Articles

Modelling Mixed Traffic Time Headway Distribution Induced by Bus Rapid Transit (BRT) in Cape Town, South Africa

Background: The safety and capacity of roadways are immensely influenced by time headways, a major traffic flow characteristic. Time headways are frequently utilized in various aspects of traffic and transportation engineering studies, including capacity analyses, studies of safety, modelling of lane-changing and car-following behaviour, and level of service assessment. Time headway, measured in seconds, refers to the distance between two subsequent passing cars moving over a single spot on the road. This paper reports the statistical modelling of the time headway distribution of a mixed traffic flow scenario caused by BRT via statistical headway distribution models. The paper posits that the introduction of BRT dedicated lane and its adopted design configuration induces anomalous traffic flows on its adjoining lanes with attendant time headway differentials, irrespective of the type of adopted design configuration for the corridor. The objectives of this study were to fit the BRT-induced time headway distribution to probability distribution models and determine the most appropriate distribution model that fits the data derived using the goodness of fit tests. Consequently, this contribution, therefore, fills the gap in research with respect to determining the precise model that fits the time headway distribution of mixed traffic flow scenarios induced by BRT. Methods: The time headway distribution data collected at four designated road segments on a multilane provincial route R27 caused by BRT dedicated lane in Cape Town, South Africa, were fitted to five probability distribution models viz, Lognormal, Inverse Gaussian, Log-logistic, Generalized Extreme Value (GEV), and Burr using MATLAB software. The fitted headway data were with respect to the traffic flows on the adjoining lanes to BRT or traffic flow ‘without BRT’. Precisely, the empirical data were collected over a three-month period using an Automatic Traffic Counter (ATC). Using ModelRisk software, the goodness of fit of the probability models was assessed by the Akaike Information Criterion (AIC), the Schwartz or Bayesian Information Criterion (SIC or BIC), the Hannan Quinn Information Criterion (HQIC), and the loglikelihood (LLH) model performance criteria respectively. The distribution model with the lowest AIC criterion and largest loglikelihood (LLH) values describe the model that best fits the headway data across the four sites. Results: Results showed that the models fitted the headway data well at each site by visual inspection of the attendant Probability Density Function (PDF) and the Probability plots (P-P). However, the Burr distribution provided the overall best fit based on the AIC and LLH values at 95% confidence and 0.05 significance levels across the four sites. At sites 02, 03, and 04, it ranked first with the lowest AIC values of 4025.99, 2595.56, 3815.36, and corresponding largest LLH values of -2008.98, -1293.76, and -1903.66, respectively, while the lognormal distribution performed best at site 01, with AIC value of 4445.14 and LLH value of -2220.57, closely followed by the Burr distribution with AIC and LLH values of 4453.05 and -2222.51, respectively. The P-values, which ranged between 0.65 and 0.80, showed the likelihood of the occurrence of the data sets under the null hypothesis. Hence the null hypothesis was accepted. Conclusion: The study concluded that the introduction of BRT dedicated lanes affects the adjoining lanes’ mixed traffic time headways’ distribution, and the headways are continuously distributed, hence fitting continuous probability distributions.

Determining Free-Flow Speed on Different Classes of Rural Two-Lane Highways

Current analytical free-flow speed models consider all rural two-lane highways as the same road type despite their different functional significance in the network. The aim of this paper is to develop a prediction model for free-flow speed as a function of speed limit and road geometric characteristics for different classes of rural two-lane highways. The research was conducted on 50 representative sections of the two rural classes of two-lane highways equipped with automatic traffic counters in Serbia. In order to develop the appropriate models, it was necessary to determine the threshold values of vehicle time headway in the free-flow for both classes of rural two-lane highways, based on the total number of 191,720 vehicles. The obtained results show that there are differences in the threshold values of free-flow time headway for different road classes. Namely, it was determined that the values of free-flow time headway for Class I amounted to 6.3 s, and for Class II to 8.4 s. The free-flow speed prediction model for different road classes showed that speed limit had the highest impact on free-flow speed for Class I and II highways, followed by horizontal curve radius and shoulder width.

Assessing The Intersected Relationship Between Land Use And Transportation Planning

This research analyses the causes of traffic congestion in urban corridors. It specifically studies the intersected relationship between land-use and transportation planning by examining Al-Madina Al Monawara street in Amman, the capital of Jordan, as a case study. Techniques implemented in data collection are personal observations, traffic counts, land use maps and questionnaires. The methods applied in analysing the collected traffic counts are: Level of Service (LOS), Automatic Traffic Counters (ATC) and Trip Attraction Analysis (TAA). The outcome of the research verified the relationship between the high level of traffic, where the traffic exceeds the actual capacity of the street by 43%, and the unregulated land use planning where 85% of the existing buildings along the street are commercial. The findings of this research will help to establish an assessment tool for testing the impacts of transportation and land use in congested developing cities. This study is important since transportation solutions receive little attention by planner’s development agendas in Jordan and the neighbouring countries.

The value of travel time: a revealed preferences approach using exogenous variation in travel costs and automatic traffic count data

This paper suggests an alternative approach to estimate the value of travel time (VTT) savings, using a case study with exogenous variation in travel costs and data from automatic traffic counts (ATC). With this revealed preferences approach, we address a possible bias of VTT estimates because of self-selection. Compared to the VTT estimates used in transport appraisals, the results produce substantially higher estimates of VTT. Unfortunately, our analysis does allow us to distinguish the self-selection bias from other possible sources of bias. The cost of using ATC data is that there is no direct information regarding the motorists, and the analysis must be done using aggregated data at an hourly interval. Still, this alternative approach may complement the results with more detailed data.

Prediction of Design Hourly Volume on Rural Roads

Design hourly volume (DHV) represents one of the most significant parameters in the procedures of developing and evaluating road designs. DHV values can be accurately and precisely calculated only on the road sections with the implemented automatic traffic counters (ATCs) which constantly monitor the traffic volume. Unfortunately, many road sections do not contain ATCs primarily because of the implementation costs. Consequently, for many years, the DHV values have been defined on the basis of occasional counting and the factors related to traffic flow variability over time. However, it has been determined that this approach has significant limitations and that the predicted values considerably deviate from the actual values. Therefore, the main objective of this paper is to develop a model which will enable DHV prediction on rural roads in cases of insufficient data. The suggested model is based on the correlation between DHVs and the parameters defining the characteristics of traffic flows, that is, the relationship between the traffic volumes on design working days and non-working days, and annual average daily traffic. The results of the conducted research indicate that the application of the proposed model enables the prediction of DHV values with a significant level of data accuracy and reliability. The coefficient of determination (R2) shows that more than 98% of the variance of the calculated DHVs was explained by the observed DHV values, while the mean error ranged from 4.86% to 7.84% depending on the number of hours for which DHV was predicted.

Characteristics of NOx and PM2.5 Concentrations in Underpass Sections

PURPOSES : The objective of this study is to figure out the trend and characteristics of fine particulate matter (PM2.5) and nitrogen oxide (NOx) concentration in underpass sections. The effect of traffic and meteorological condition on PM2.5 / NOx concentration was analyzed using field monitoring data. METHODS : Based on the literature review, PM2.5 and NOx concentration data were monitored using DustTrak II aerosol monitoring system and Serinus 40 oxides of nitrogen analyzer, respectively. Meteorological and traffic information was collected using automatic weather system and traffic volume counter, respectively. RESULTS : PM2.5 has a positive and negative correlation with relative humidity and wind speed, respectively. Meanwhile, NOx was found to have no correlation with meteorological conditions. The NO/NO2 ratio tends to change with traffic volume, indicating higher correlation between NO and traffic volume; the observed NO2 is mostly a secondary material produced by NO oxidation. CONCLUSIONS : Our study provides clear characteristics of NOx and PM2.5 and correlations with meteorological and traffic information in the underpass sections. It is found from this study that the increase in wind speed causes reduction in the concentration of PM2.5 owing to the diffusion and dispersion phenomena. On the other hand, the meteorological conditions were found to barely have correlations with NOx concentrations in this study. The traffic volume could significantly affect the NOx concentration and NO / NO2 ratio, which is directly correlated to the emissions from vehicles.

Comparative Evaluation of Malaysian HCM 2011 and US HCM 2010: Ramp Merging Expressway

It is important for traffic engineers in Malaysia to comply with the relevant and appropriate standards and manuals to determine the performance of highway facilities that will provide accurate result reflecting the existing operation of highways. This paper provides the comparative study in performance evaluation of ramp segment between Malaysia Highway Capacity Manual 2011 (MHCM 2011) and US Highway Capacity Manual 2010 (USHCM 2010). The study was conducted by analyzing data collected, obtained by using Trax Apollyon Automatic Traffic Counter at Km 12, Grand Sepadu Expressway, Selangor. The evaluation of performance for ramp segment was measured by density.. Both densities measured using MHCM 2011 and USHCM 2010 were statistically compared with empirical data provided and the accuracy of both manual was calculated by using the root mean square error (RMSE) for each manual. Correspondingly,RMSE for MHCM 2011 showed lower value which was at 2.44 compared to 2.70 for USHCM 2010. Results showed that MHCM 2011 was more accurate in measuring the density for the ramp section as it has lower value.

Assessment of level of service (LOS) for entrance ramp merging by using HCM US 2000 and HCM US 2010

Congestion is a normal occurrence on the urban Malaysian expressway system, usually associated with areas having entrance ramp, exit ramp and weaving section. A good practice for expressway system can be determined by the efficiency of the traffic operation itself. Thus, this research paper provides the assessment of level of service for entrance ramp merging using US HCM 2000; US HCM 2010 and empirical data as the indicator. Study was conducted at KM 12, Grand Sepadu Expressway, Selangor and the data were collected by using TRAX Apollyon Automatic Traffic Counter. An analysis was conducted and the RSME result shows that the plotted data are successfully developed and validated in these studies.

The effects of the 2013 floods on Germany’s freight traffic

This article analyzes the spatio-temporal effect of the 2013 floods on freight traffic in Germany by using automatic traffic counter data. The methodology uses a proven time-series outlier detection and identification technique to endogenously determine if a counter was affected during the flood and estimate the magnitude and duration of the change in the number of vehicles passing through it. This is the first paper able to quantify climate-related variations in traffic across all the counters of a national network. Results show variations on 10% of all counters and 23% of all main roads. Results allow us to trace the configuration of disrupted and detour routes, recovery times, and the total effect on the network. Our findings serve as an input to other studies on the impact of exogenous events on the transport system and contribute towards the formulation of public policies to improve road resilience.

Analysis of Incremental Load Damaging Effects of Overloaded Trucks on Federal Highway Pavement Structures in Nigeria

The study is to assess the present serviceability rating of Nigerian highways and the load damage effects of overloaded trucks. The researchers used the American Association of State Highway and Transportation Officials (AASHTO) methods. In this study, the highway section of Lokoja-Abuja, Ilorin-Jebba and Abakiliki-Ogoja via Mbok roads were selected, and data were collected through an axle-load survey, automatic traffic count and from secondary sources. The rate of gross vehicle weight violation was found, ranging from 20% to 94% of the axle load distribution across the studied network. Comparing the overloaded vehicle damage factor (V.D.F.) and standard V.D.F., the range was from 1.2 to 41.34 times across the road networks studied, and this explained why the pavement structures of Nigerian roads tend to deteriorate during its service life rapidly. Present serviceability rating was estimated at 3.45, 4.41 and 3.35 for Lokoja-Abuja, Ilorin-Jebba and Abakiliki-Ogoja roads respectively, showing depletion from their initial conditions. The damaging effects of the HGV are more severe at Lokoja-Abuja Road (with g = 0.30), followed by Ilorin-Jebba Road (with g = 0.35) and in Abakiliki-Ogoja Road (with g = 0.43). The heaviest overload of 94% of the 6-axle vehicles plying at the Lokoja-Abuja road could explain this intense damaging effect on the road pavement.

A methodology to design and assess scenarios within SULPs: the case of Bologna

The paper, focusing on the importance to develop sustainable urban logistics plan (SULP) and to implement a demand model system for the assessment of future scenarios, presents a methodology for setting up a SULP modelling, using different sources of data (i.e. automatic traffic counts, floating car data, surveys with retailers and transport operators). The methodology is applied to the functional urban area (FUA) of Bologna (Italy). In particular, it was used for assessing the new city logistics scenarios of the Bologna’s SULP where a set of measures have been proposed for improving city sustainability and livability.

Estimating Road Traffic Capacity

This paper proposes a novel passenger car equivalent and capacity estimation methods that determine the effect of deceleration and acceleration performance of heavy goods vehicles on the traffic flow and estimate the capacity to facilitate rescheduling container carriers. The development of the new methods considers the driver’s perception of time and braking competency level, and the out of the box vehicle displacement approach. The safety gap between the following and leading vehicle should provide sufficient time and space for the driver to bring the vehicle safely to a standstill, to prevent accidents and facilitate enough space for maneuvering. As a case study, the authors have collected and utilized the automatic traffic counters data and the average annual daily flow data from manual counting for the road connecting the Liverpool containership port with North-West England and the rest of the UK. However, the capacity estimation method is suitable for all urban roads and streets that have controlled intersections in the UK and the USA. The authors have found that the passenger car equivalent method is directly proportional to the vehicle’s speed, and gross mass and the capacity method is inversely and directly proportional to perception time and braking competency level, respectively. Also, building an extra lane will allow meeting the ports targets.

Applicability of an automatic pneumatic–tube–based traffic counting device for collecting data under mixed traffic

Traffic volume and composition data can be collected using several techniques such as manual, camera video recordings and automatic traffic count devices installed across the road pavement. An automatic traffic count device is often used for long hours of traffic data collection exercises. In view that the accuracy of the data is an important aspect of data analysis, this paper discusses the applicability of an automatic traffic count device to be used for traffic volume and composition data collections based on Malaysian vehicle classification system, i.e. where traffic is characterised by various types of vehicles or mixed traffic. The automatic traffic count (ATC) used in the study was the pneumatic tube-based equipment known as Metrocount@5600. The data used for validating the ATC was obtained using a video recording technique. The data was collected at four different sites to ensure the result of the analysis is reliable. A video camera and ATC were installed at each of the sites considered in the study. Traffic volumes and compositions from video recordings were extracted manually based on five classes of vehicles, i.e. cars and small vans, medium trucks and lorries with two axles, large trucks and lorries with three and more axles, buses and motorcycles. The ATC was set to classify vehicle types using one of the equipment’s default setting, i.e. 13 classes (Scheme F). The data retrieved from the ATC was reorganised based on the vehicle classifications used in the data collected using the video recording technique. Twenty datasets of vehicles composition from four sites were used in the analysis. The result of the statistical analysis showed that there is no significant different in traffic volumes and compositions obtained using both techniques. The finding implies that an automatic pneumatic-tube-based traffic counting device such as MetroCount@5600 with scheme F can be used as an alternative technique to collect traffic volumes and compositions data based on five standard classes of vehicles classification system.

Implementation of chosen risk index during car-following behaviour under wet weather condition

This study aims to examine the effects of wet weather on accident consequence during car-following behaviours. The study analysed drivers’ car-following headway on two-lane highways along passing and no passing zones associated with passenger cars and heavy goods vehicles (HGV). The speed and time gap of more than 200,000 vehicles were recorded during dry and wet weather at 4 specific sites in Peninsular Malaysia using Automatic Traffic Counter with pneumatic tubes. Rainfall data were acquired from the nearest rain gauge station. Chosen Risk Index (CRI) was used to characterize and evaluate the accident consequence caused by wet weather incidence. The results disclose that the drivers are more cautious to avoid accident severity during wet weather compared to dry weather irrespective of vehicle type and highway features. This result is evidenced by lower CRI values during wet weather compared to dry weather. The data shows that under wet weather condition the speed that gives lower risk of accident is in the range of 47.3 to 73.9 km/h and 56.5 to 74.0 km/h i.e. which associated with CRI values in the range of 0.60 to 0.75 and 0.53 to 0.79 at passing and no-passing zones, respectively. These findings are useful for the improvement of roadway design and the implementation of traffic safety interventions.

IMPLEMENTATION OF A PARK & RIDE SYSTEM IN SARAJEVO / IMPLEMENTACIJA MODELA PARK & RIDE SISTEMA U SARAJEVU

Sarajevo is the capital city of Bosnia and Herzegovina and represents the largest urban, cultural, economic and transport center, with seven major roads connected to other parts of the country. A large number of cities in the world have a problem with parking requirements, and Sarajevo is not an exception. Because of that, there is a need for reducing traffic flows in the nearest city center by using “smart solutions” that advocate vignettes or other billing for entry into the city center, such as the Park & Ride Concept, with with the aim of reducing pollution and environmental pollution. The Park & Ride system is a highly functional way of reducing the number of vehicles coming to a larger city, and it works by getting public transport terminals closer to each other, rebuilding or building a new parking lot where drivers park their passenger cars and continue the route with public transport to the very center of the city. Since Park & Ride facilities are expensive and spend fairly precious city land, so their planning and construction needs to be accessed extremely thoroughly and rationally. It is extremely important to have a set of criteria according to which investment decisions will be made, which does not mean that their number in advance guarantees a successful planning process. Traffic system analysis in Sarajevo is based on the analysis of the load and number of passenger cars, an analysis of the number of public parking lots in the city center and the possibility of implementing the Park & Ride system. According to data from automatic traffic counters, there are 29,822 AADT vehicles wich enter the city center and 32,877 AADT vehicles of wich leaving the city. There are frequent queues that last for 2-3 semaphore cycles on the stock, which represents the need of building innovative solutions that make up a part of every concept of “Smart Cities”. In this paper, AHP method has been applied which provides a good basis for multi-criteria evaluation and ranking of future Park & Ride facilities. The AHP method is also suitable for use in cases where pure economic criteria may not be sufficient to make final decisions. This paper is based on the critical analysis of previous experience and the research carried out by the author, and it defines the main criteria that need to be applied in the planning of Park & Ride facilities development. Eight locationst are detected at the very entrance to the nearest city center of Sarajevo, which are directly linked to the public transport infrastructure, which would be ideal for implementing the Park & Ride concept.

The effectiveness of a 20 mph speed limit intervention on vehicle speeds in Bristol, UK: A non-randomised stepped wedge design

Twenty mph (32.2 km/h) speed limits across urban areas are becoming a widespread tool for public health and road danger reduction globally. Determining the effectiveness of these interventions on motorised vehicle speeds is a crucial first step in any logic model that seeks to associate 20 mph speed limits to improved health and wellbeing outcomes. However, little is known about how the introduction of 20 mph limits affects speeds. This paper presents the findings from a novel comprehensive academic evaluation of the adjusted effects of a 20 mph sign-only city-wide intervention on vehicle speeds. This is based on a natural experiment that took place in Bristol, UK. Applying a quasi-stepped wedge design, speeds of 36,973,090 single vehicles, recorded by Automatic Traffic Counts before and after the 20 mph intervention, were analysed. Generalized linear mixed models were used to control for confounding variables. Results showed an unadjusted speed reduction of 4.7 mph (7.56 km/h) and an adjusted speed reduction of 2.66 mph (4.28 km/h) over two to three years. Some variability due to time variables was detected, with speed reductions being larger during night time, at weekends, and in summer months. The roads that did not receive the 20 mph intervention also saw a small reduction in speed (0.03 mph). The findings indicate that the sign-only 20 mph intervention was successful in lowering individual vehicle speeds. Policy makers are encouraged to implement a careful monitoring of the effects of 20 mph speed limit interventions on vehicle speeds in order to enable a meaningful evaluation of potential public health benefits.

Traffic Noise Assessment at Residential Areas in Skudai, Johor

Vehicles passing by on roadways in residential areas may produce unpleasant traffic noise that affects the residents. This paper presents the traffic noise assessment of three selected residential areas located in Skudai, Johor. The objectives of this study are to evaluate traffic characteristics at selected residential areas, determine related noise indices, and assess impact of traffic noise. Traffic characteristics such as daily traffic volume and vehicle speed were evaluated using automatic traffic counter (ATC). Meanwhile, noise indices like equivalent continuous sound pressure level (LAeq), noise level exceeded 10% (L10) and 90% (L90) of measurement time were determined using sound level meter (SLM). Besides that, traffic noise index (TNI) and noise pollution level (LNP) were calculated based on the measured noise indices. The results showed an increase in noise level of 60 to 70 dBA maximum due to increase in traffic volume. There was also a significant change in noise level of more than 70 dBA even though average vehicle speed did not vary significantly. Nevertheless, LAeq, TNI, and LNPvalues for all sites during daytime were lower than the maximum recommended levels. Thus, residents in the three studied areas were not affected in terms of quality of life and health.

Assessment of traffic noise due to transverse rumble strips at residential areas

Transverse rumble strips (TRS) are commonly being installed to alert the drivers through sound and vibration effects. The sound produced affects the existing traffic noise level which caused noise annoyance to the nearby residents. This study aims to assess the traffic noise due to TRS at residential areas by determining the roadside noise levels, traffic and road characteristics and evaluating the relationship between these parameters. Middle overlapped (MO), middle layer overlapped (MLO) and raised rumbler (RR) TRS profiles with same thickness were selected. The measurements of roadside noise levels and skid resistance were conducted using sound level meter (SLM) and British pendulum tester (BPT) respectively. Traffic characteristics were evaluated using previous data measured using automatic traffic counter (ATC). In overall, MLO produced highest roadside noise levels with increase of 20.5dBA from baseline. Generally, the increase of roadside noise level due to TRS is strong with speed, weak to medium with skid resistance of TRS and no relationship with traffic volume. Based on three TRS profile types, MLO is not suitable to be installed on the roadways adjacent to the residential areas as the increase of roadside noise level is significant which is more than 5dBA compared to MO and RR.

Impact of Rainfall on Multilane Roundabout Flowrate Contraction

In this study, roundabouts at two sites in the Malaysia were investigated under rainy and dry weather conditions. Two automatic traffic counters per roundabout arm as well as two rain gauge stations were used to collect data at each surveyed site. Nearly one million vehicles were investigated at four sites. Vehicle volume, speeds and headways for entry and circulating flows were collected continuously at each roundabout about arm for six weeks between November 2013 and January 2014. Empirical regression technique and gap-acceptance models were modified and used to analyze roundabout capacity. Good fits to the data were obtained; the results also fit models developed in other countries. It was assumed that entry capacity depends on the geometric characteristics of the roundabout, particularly the diameter of the outside circle of the intersection. It was also postulated that geometric characteristics determine the speed of vehicles around the central island and, therefore, have an impact on the gap-acceptance process and consequently the capacity. Only off-peak traffic data per light, moderate or heavy rainfall were analysed. Peak traffic data were not used because of the presence of peak traffic flow. Passenger car equivalent values being an instrument of conversion from traffic volume to flow were modified. Results show that, average entry capacity loss is about 22.6% under light rainfall, about 18.1% under moderate rainfall and about 5.6% under heavy rainfall. Significant entry capacity loss would result from rainfall irrespective of their intensity. It can be postulated that entry capacity loss under heavy rainfall is lowest because the advantage enjoyed by circulating flow would be greatly reduced with increased rainfall intensity. The paper concluded that rainfall has significant impact of flowrate contraction at roundabouts.

Comparison of Traffic Speed Before, During and After “Banci Lalu Lintas” at Federal Road ft005

Traffic engineering uses engineering methods and techniques to achieve the safe and time efficient movement of people and goods on roadways and it depends on traffic flow. The three main parameters of a traffic flow are volume, speed and density. Speed is an important transportation consideration because it relates to safety, time, comfort, convenience, and economics. This study is to show the difference of traffic speed for before, during and after a primary traffic survey called “Banci Lalu Lintas”. This study also is conducted at Federal Road FT005 with collaboration of Jabatan Kerja Raya (JKR). In achieving the goal for this study, traffic speed is recorded by using two methods which are manual method and Automatic Traffic Count (ATC). For before and after the survey, manual method is used and the data is collected for 15 minutes, while during the survey, ATC is used in collecting data for 24 hours per day in a week. The data obtained where the mean speed is recorded and is compared as well as analyzed between three categories which are before, during and after “Banci Lalu Lintas” and using statistical analysis. In result, the speed of vehicles for during the survey is the lowest compared to before and after survey where the differential percentage are 6.68% and 23.64% for before – during and during – after “Banci Lalu Lintas”. The study concluded that drivers tend to decrease their vehicles speed when there is an event or unexpected conditions on the road. The result is important for future development and safety of road in Malaysia.