In Egypt, it is believed that speed humps are the cheapest and best solutions to reduce vehicles speed and thus reduce the number of potential accidents. Due to the lack of specifications in Egypt that govern the installation of speed humps, they were spread randomly and with different dimensions without adequate studies. Consequently, this practice can cause adverse effects on the road users and the surrounding environment. For this purpose, a questionnaire was designed to discuss the different effects of using speed humps in Kafr El-Sheikh city as a typical model in the Egyptian cities. To verify that the questionnaire is appropriate for the intended task, it was evaluated by 30 respondents aged 18 years and over. After the trial process, the required corrections were made to the proposed form of the questionnaire. Then, final questionnaires were distributed and 1000 responses were collected from all road users, whether they were pedestrians, drivers, and owners of vehicles or vehicle repairmen by using face-to-face interviews. The responses were analysed using SPSS program. The results reflected that the installation of speed humps contributed greatly to reduce vehicles speed, the flow of traffic and accidents rate. On the other hand, the results proved that humps also contribute significantly to the environmental pollution, damage to the pavement and vehicles especially when they are poorly designed and located. The majority of respondents attributed the random spread of the speed humps to the weakness of the authorities in law enforcement and the prevention of the installation of new humps without authorization. Finally, with the widespread use of speed humps and with the exception of the positive impact on traffic safety, it also has negative impacts on both the economy and the environment. Finally, the use of speed humps can cause many harmful effects to the neighbourhood, if there no strict control on its installation process. Unless specifications and some standards should be strictly followed, other means of traffic calming measures should be considered.
In Egypt, speed humps are often thought as the best and cheapest tool to reduce vehicles speed and consequently decrease the number of potential accidents. The lack of standards in Egypt led to the installation of a number of speed humps with random dimensions and without good justification. They have become in many cases a source of disturbance and discomfort to drivers and passengers especially when they are poorly designed and located. So, standard design guidelines are disparately required. Three streets from the urban road network of Kafr El-Sheikh city were chosen to collect field data. A total of 51 speed humps were chosen for field data survey. Although there are many design shapes of speed humps, the study focused only on the sinusoidal type. As observed in the field survey, it was found that more than 74% of the observed road humps were of the sinusoidal type. The screening process resulted in only 24 sinusoidal shape speed humps from the 51 speed humps firstly chosen. For speed measurement, data were collected by installing a recording camera beside the road carriageway of each speed hump for an hour time interval. Spot speed for three types of vehicles was measured from the recorded videos for each site by using the logger program software. The operating speeds (V85%) at humps locations have been obtained for different vehicles. Regression analysis models were developed to represent the relationships between the operating speeds (V85%) at humps locations for motorcycles, passenger cars vehicles, and microbuses and three variables, hump length, hump height, and the spacing between successive speed humps. Generally, the results demonstrated that spot speed is significantly influenced by speed hump geometric dimension and the spacing between them. Finally, the developed regression lines can be used easily for setting the geometric dimensions for each proposed hump location.
This paper examines the transferability of the Safety Performance Function (SPF) of the Highway Safety Manual (HSM) and other 10 international SPFs for total crashes on rural multi-lane divided roads in Egypt. Four segmentation approaches are assessed in the transferability of the international SPFs, namely: (1) one-kilometer segments (S1); (2) homogenous sections (S2); (3) variable segments with respect to the presence of curvatures (S3); and (4) variable segments with respect to the presence of both curvatures and U-turns (S4). The Mean Absolute Deviation (MAD), Mean Prediction Bias (MPB), Mean Absolute Percentage Error (MAPE), Pearson χ2 statistic, and Z-score parameters are used to evaluate the performance of the transferred models. The overdispersion parameter (k) for each transferred model and each segmentation approach is recalibrated using the local data by the maximum likelihood method. Before estimating the transferability calibration factor (Cr), three methods were used to adjust the local crash prediction of the transferred models, namely: (1) the HSM default crash modification factors (CMFs); (2) local CMFs; and (3) recalibrating the constant term of the transferred model. The latter method is found to outperform the first two methods. Besides, the results show that the segmentation method would affect the performance of the transferability process. Moreover, the Italian SPFs based on the S1 segmentation method outperforms the HSM and all of the investigated international SPFs for transferring their models to the Egyptian rural roads.
In order to fight against over-speeding, the government and people in Egypt resorted to the installation of speed humps without adequate studies. On this basis, speed humps became widespread in most of the Egyptian roads in a semi-random way. It has been observed that the pavement condition of the roads has deteriorated in the vicinity of these humps. For impact assessment of speed humps on the pavement condition index (PCI), three roads link Kafr El-Sheikh city with three major towns in Kafr El-Sheikh governorate were selected to conduct PCI survey. The results indicated that the presence of speed humps contributes greatly to reduce the pavement condition index (PCI) values. It should be mentioned that the average reduction in PCI values ranged between 15% and 22% due to the presence of speed humps. Also, the most frequently observed distress on the pavement sections including humps considered for the selected roads was Raveling and Rutting. Accordingly, to avoid the pavement defects at the locations where the speed humps are installed, it is proposed to study the structural section of the road in the vicinity of the speed hump to resist the braking force and speed reduction effect.
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