Estimating average daily traffic using alternative method for single carriageway road in Southern Region Malaysia

Average Annual Daily Traffic (AADT) and Average Daily Traffic (ADT) are two parameters that are commonly required by traffic engineers and road designers to design and analyse the traffic operational performance of a road segment. In Malaysia, ADT is normally used to forecast the volume of traffic in the design year as well as to design the pavement thickness. Basically, ADT can be generated using expansion factor estimates from Peak Hour Volume (PHV). Current practice in Malaysia uses an expansion of 10% to estimate ADT from PHV. This paper discusses the results of a study carried out to establish a model for estimating ADT using PHV for single carriageway road. The 24-hours traffic data were collected at 9 sites in the districts of Johor, Malaysia for the period of 14 days. The 7-days data were used to establish the model and the other 7-days data were used to validate the model. For validation purposes, the absolute percent error (APE) for each estimate of ADT obtained from the model was calculated and compared with observed ADT. The statistical test at 95% confidence level was conducted to determine the significance difference between the ADT from actual data and the estimate ADT from model. The result shows that a power-formed trend line (y=axb) suits to the observed data with the coefficient of determination of about 0.90. Validation result shows that the ADT for the model has lesser APE compared with the ADT estimated using the factoring approach. A comparison of both estimated and actual ADT values using t-Test shows that there is no significant difference between the estimated ADT using models and the actual ADT. However, the ADT estimated using the expansion factor of 10% shows the vice versa. Such a finding implies that the model obtained from this study predicts ADT accurately than the current practice

Research Article Headway Distributions Based on Empirical Erlang and Pearson Type III Time Methods Compared

Abstract: The study is aimed at exploring empirical headway derived from Erlang and Pearson type III distribution and comparing the resultant distributions. The Erlang distribution is a simplified form of the Pearson type III. In circumstance where vehicle overtaking is very limited and the ensuing headway values are small, Pearson type IIIor the Erlang distribution may be used to represent the headway frequency distribution. Based on the hypothesis that headways derived from Erlang and Pearson type III distribution will not differ significantly, headway study was carried out in Kulai, Malaysia under dry and daylight conditions. Twenty four hour volume, speed and headways and vehicle type data were collected continuously for eight weeks. The survey data were supplemented with highway design information culled from the Malaysian Design Manual. Empirical headway data were computed using Pearson type III and Erlang distribution methods. Results show that the difference between estimated headways using both techniques is very marginal. The study concluded that in cases where overtaking induces minimal headways, the Pearson type III or the Erlang distribution may be used to represent the headway frequency distribution. However, Pearson type III distribution has to be modified in circumstances where the probability of observing headway increases

Calibration of microsimulation model for tight urban diamond interchange under heterogeneous traffic

Traffic simulation models have been widely used to evaluate design alternatives and to help decision-makers to select best design option for prevailing traffic conditions. This study focuses on application of microsimulation model to the performance assessment of Tight Urban Diamond Interchange (TUDI) located in a congested urban setting with population more than 9 million and current transport demand up to 13.5 million daily motorized trips. Geometric and operational data was collected by conducting multiple site visits. Traffic volume data showed the heterogeneous nature of traffic. Microsimulation model; VISSIM was applied and appropriateness of this model and the proposed methodology was assessed based on maximum queue length as Measure of Effectiveness (MOE)

Befogged

Porous Asphalt (PA) is known as a highly permeable asphalt surface that design to be permeable pavements for stormwater control and reduce the stormwater runoff. However, the structure is subjected to damage from cracking, rutting, stripping, and rapid aging under the effects of repeated vehicle loading, hot climates, and heavy rainfall. To overcome this, PA needs to modify using high tensile strength like steel fiber. Thus, this study aims to evaluate the performance of PA with the addition of steel fiber and overcome the issue that is related to PA. A mixture contains varying percentages of steel fiber were assessed to check which samples gives the best performance as per the requirement by using laboratory tests which are LA Abrasion, Resilient Modulus, Marshall Stability, and Density. The results show that the additions of 0.6% steel fiber give the lowest value of abrasion, while 0.5% fiber content contributes the highest value of Resilient Modulus and Marshall Stability respectively. PA mixtures modified with steel fiber produce the performance enhancement of PA as a road surfacing material. It is concluded that the asphalt mixtures containing steel fibers could increase the stability and strength of the mix

Effectiveness of and public perception about the installation of transverse rumble strips with road studs

The installation of transverse rumble strips (TRS) is a common practice to reduce vehicle speed and alert drivers on the roadway. However, the combination of TRS with road studs to enhance traffic safety is still not widely used by local authorities. This paper aims to evaluate the effectiveness of and the public perception about the installation of TRS with road studs. A field observation was carried out on the TRS road section with and without road studs for speed evaluation. A questionnaire survey was also conducted to assess the public perception towards the installation of this measure. The results indicate that the mean speed at the TRS road section with road studs was lower than the speed at the TRS road section without a road stud and its effectiveness was evaluated using a statistical test. Responses from the questionnaire survey showed that respondents agree that both TRS with and without road studs can reduce speed effectively. Respondents also believed that the installation of road studs might cause damage to the vehicle. This paper concludes that TRS installed with road studs effectively reduces speed which is consistent with the results of the public perception survey

The effect of vehicle weight on the sound produced by transverse rumble strips

Transverse rumble strips (TRS) are commonly used as traffic calming measure in the vicinity of premises. So far research have been extensively concentrated on the effect of vehicle type and speed on the noise produced by TRS, and very little research focused on the effect of vehicle weight. Do these vehicles produce extremely higher sound level parallel to their heavier weight? This is important as in reality, traffic flow consist of light, medium and heavy vehicles, which are also important sources of noise. This study investigated the effect of vehicle weight, such as gross vehicle weight (GVW) when transited on TRS, particularly with emphasis on impulsivity content. The objectives of this research were to: (1) determine the effect of GVW on noise generation when a vehicle transits on TRS and (2) assess the effect of GVW on the impulsivity of noise. Data from vehicles with weight between 800 kg - 8000 kg were collected based on previous research where these vehicles were tested on speed values of 30km/h and 50km/h. It was found that when the vehicles transited on TRS, the generated noise was strongly related with the vehicle weights (R2=0.71) higher than those normal road surface (R2=0.49). However, the changes of noise were not well represented by direct relation. It was found that TRS can increase and decrease the sound pressure level, depending on GVW, but on average, TRS can increase the sound pressure level by 1 dBA. Despite that, TRS was found to have an impulsive characteristic within the tested speed range. This finding can facilitate the authority to evaluate the environmental noise produced by TRS

Effect of rainfall on the compaction of dense-graded hot mix asphalt

Unpredictable tropical weather particularly rainfall can possibly interfere the compaction work of asphalt pavement. Heavy rainfall often leads the asphalt to cool and harden quickly and become difficult to compact. This study evaluates the effect of rainfall on the compaction properties of hot mix asphalt (HMA). A dense-graded mix of AC14 was prepared using 60/70 PEN bitumen and compacted at different temperatures. A handy steel roller was used to compact the slab samples with the size of 305 mm × 305 mm × 50 mm. The cooling rate and time available for compaction (TAC) were monitored using thermocouple under different levels of artificial rainfall and wind speed generated in the laboratory to simulate the wet conditions. The slabs were then cored at 100 mm diameter and tested for the volumetric properties. The result shows that environmental conditions and mix temperature determines the cooling rate and final density of the asphalt pavement. In addition, the TAC decreases as the compaction temperature reduces. Alternatively, working under light and moderate rainfall during the asphalt paving operation reasonably achieves the required degree of compaction (DOC). However, paving works under heavy rainfall reduce TAC, compactibility and density of the asphalt mat

Transportation mode choice binary logit model: a case study for Johor Bahru city

The mode choice stage in transportation planning is the analysis process to estimate the number or percentage of trips performed by each mode of transport. In practice, the number of trips is used to estimate the demand for each mode of transport. Such information is important for planning and designing transportation facilities in an urban area. A mathematical model of individuals' mode choice is usually required in such an analysis. This paper discusses the result of a study carried out to evaluate the attributes that influence the mode choice of transport in Johor Bahru city by interviewing the individuals living for more than one year in the study area. The investigation conducted through one of attitudinal survey techniques known as stated preference survey. Stated preference survey conducted on a random sample of 384 respondents. Investigated attributes have been identified in analysis stage by applying binary logistic regression analysis procedure before deriving binary logit model for individuals' mode choice of transport in Johor Bahru city. Based on stated preference survey and logistic regression analysis of data, the model of mode choice of transport in Johor Bahru has been derived and attributes of age, income, vehicle ownership, comfort of car, reliability of bus service, affective motives and instrumental motives were found statistically correlated to the mode choice of transport in Johor Bahru

Effects of black rice husk ash on asphalt mixture under aging condition

The scarcities of natural resources and increment in the waste production rates have promoted efforts to investigate the potential incorporation of various by-products in roads construction and maintenance. Various types of waste materials have been investigated, assessed and evaluated for utilization and practiced in the industry. Reusing of waste materials such as black rice husk ash (BRHA) in asphaltic concrete (AC) was considered as one of the proper management of the waste, which ensure economic and environmental benefits. This study was investigated BRHA effects on the properties and performance of asphalt mixture under different aging condition. The BRHA was added in the AC14 mixture in a proportion of 0%, 2%, 4% and 6% by weight of bitumen. The optimum bitumen content was 5% and the bitumen used was 60/70 penetration grades. The asphalt mixture for each fraction was prepared in three different aging conditions i.e. un-aging (UA), short term aging (STA) and long term aging (LTA). The performance of the asphalt mixtures was evaluated by Marshall Stability and resilient modulus. The results indicate that asphalt mixtures consisting of BRHA have exhibited better performance in term of stability and resilient modulus when compared to the conventional asphalt mixtures. The short term and long term aging mixtures considerably produced higher performance than the un-aging mixtures. However, the LTA performed better than of the STA mixtures. Finally, the optimum additional percentage of BRHA was in the range of 4 - 6% since its produce excellent values in most circumstances

Waste cooking oil as bio asphalt binder: a critical review

The modification of binder with waste cooking oil (WCO) for paving materials indicates the implementation of recycling practice with environmental issues concern, thus improving the proper management of this waste product. This paper presents a critical review of the WCO utilisation as a modifier to enhance binder properties. The review was focuses on the evaluation of WCO in asphalt binder modification and asphaltic concrete mixture. Basically, oil-based modification by using WCO in paving material provides a promising waste material potential in improving the engineering value in terms of rheological and mechanical performance for modified binder and asphalt mixture. It is expected that the addition of this modifier in binder gives superior performance and is comparable with the conventional binder