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Current research work investigates road user’s comprehension of different traffic control devices. Sample demographics were taken into consideration such as age, gender, and educational background. Twenty regulatory and warning signs were examined in this study. These signs vary from simple ‘No parking’ sign to more tricky ones such as ‘Divided highway’ sign. In addition, the questionnaire includes other questions related to road safety, condition of roads signs, and feeling of safety as a driver and as a pedestrian. These signs were selected based on their popularity among other road signs. The selected sample was over 100 people from different regions in Iraq (mainly southern provinces and the capital Baghdad). Only 16 % of selected sample answered with yes when asked about feeling safe as a driver, whereas 29% feels safe as a pedestrian. None of the respondents got all the 20 signs meaning correct, and the highest percent of correct sign meaning was associated with pedestrian crossing sign (98.2%). On the other hand, flagger man sign (work zone sign) had the lowest correct score of (19.8%). Overall Average of correct signs meaning was (68.5%). Approximately, 25% of traffic signs have scored less than 50%, and 75% of traffic signs scored more than 50% correctness score. A great work needs to be done to educate and spread adequate material that explains uses and meanings of different road signs.

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Nowadays, the increasing demand for road transport makes maintenance and repair of road infrastructures key tasks for road engineering. The current experimental work consists of laboratory model experiments to understand the conduct of sand as a subgrade under dynamic load and its effect on the flexible pavement and base layer. Geogrid reinforcement was applied at the interface between the base and subgrade using SS2 type of geogrid. The road layers were exposed to harmonic dynamic load with two load amplitudes 10 and 15 kN and two frequencies 0.5 and 1 Hz. The vertical stresses in the road layers are measured using stress gauge sensor. It revealed that when laying the geogrid between the base course and subgrade and when base course thickness is 150 mm, the stress and displacement decreased with increase in the frequency and load amplitudes. But in the case of reinforcing layer at the center of the base course layer, the displacement decreased with increase in the frequency and loads except for one case when the load was 15 kN and frequency 0.5 Hz. It can be suggested that the maximum vertical displacement increased with the increase of base course thickness for both reinforced and unreinforced base layers. Also, it can be observed that the vertical stress increased by increasing the base course layer-thickness for unreinforced models.

The most important parameter for airport operator is safety. Minimizing any possible risks for passengers, crew, and equipment is the main objective of applying safety management systems at airports. The rubber deposits that accumulate on the runway surface due to aircraft operations is one of the most critical factors that directly effects on the skid resistance value of the airport runway. Four common techniques are applied throughout the world for mitigating this rubber strip water blasting, chemical, shot blasting, and mechanical. Every technique has its pros and cons in terms of cost, efficiency, environmental effect, and damage to pavement surface. The current design involves developing an expert system that takes into account the parameters that may support choosing the optimal method for rubber removal in certain situations. These parameters include airport classification, cost involvement, accessibility, pavement damage concerns, environment damage or side effects, and any additional factors such as noise. The system is developed using webpage-based Expert System builder ES-Builder. Simple user interface, windows based, easy to build the decision tree are the major concerns for choosing this program to build the proposed expert system. The expert system follows a deduction process, until the expert system makes the final conclusion according to user selected answers. The proposed expert system works very well when selecting appropriate answers taking into consideration specific characteristics for each airport category. Faulty conclusions could be given if the user does not use the appropriate parameters related to the airport category. There is no optimum solution, every airport situation is different, and the solution or the recommended method varies from one airport to another.