Different Types of Incidents

Based on the geographical location of cities or countries, several types of incidents can be found in the literature. For example, Araghi et al. [7] identified ten types of incidents in the Greater London Area: Broken-down vehicle, broken-down lorry, accident, flood, fuel spillage, gas leak, fire, police incident, collapsed manhole, and traffic light failure. Each of these incident types may have several sub-categories. For example, accidents can be of different kinds: Rear-end collision, side-impact collision, head-on collision, rollover, singlecar accident, multiple vehicle pile-up, etc. [4]. The annual number of deaths per 100,000 people due to road accidents in 2017 is shown in Figure 10.1 for different countries all over the world. In general, the types of incidents vary with the traffic conditions (i.e., speed limit, traffic flow), geographical attributes (i.e., the width of the roads, capacity), as well as weather (i.e., rainfall, fog, snow). Moreover, the types of incidents recorded from highways or freeways can be significantly different from the incident types that are recorded from arterial roads. Considering all these variations, we can broadly classify the traffic incidents into six categories: Vehicle breakdown (disabled vehicles), accident (crashes and collisions), obstacle on the road (stationary and abandoned vehicles), roadblock or diversion, car on fire, and miscellaneous (which includes other types of incidents such as fuel spillage, traffic light failure, etc.). These types of incidents are mostly common for all cities, as mentioned in past studies [1][9],

FIGURE 10.1

Annual death rate from road accidents in 2017 [8].

Causes of Incidents

Traffic incidents can be caused due to several reasons. Although adverse environmental factors or poor vehicle conditions may lead to traffic incidents, humans can also be responsible for a large percentage of traffic incidents [3]. Below are the most common causes of traffic incidents:

• 1. Drivers: There are many laws and rules concerning driving in every country since in many cases drivers are solely responsible for road accidents and crashes. Distracted driving brings about 25% of the incidents all over the world, which includes texting, eating, talking, or doing other tasks while driving. Apart from these causes, drunk driving and sleep deprivation are even more dangerous and pose a great threat to all road users. In addition, reckless or rash driving, speeding, and violation of traffic rules and traffic lights can all lead to mishaps on the roads.
• 2. Defects in the vehicle: Vehicle breakdowns are mostly caused by flaws in the vehicles, such as brake failure, failure of steering system or lighting system, tire burst, etc. Therefore, the owners of the cars should take their cars for regular maintenance to avoid such incidents on roads.

• 3. Poor environmental conditions: Rainfall, snowfall, fog, etc. cause hindrances in smooth driving, and therefore may lead to traffic incidents. Due to rainfall and snowfall, the roads become slippery. As such, vehicles tend to skid more due to lower friction with the roads. Moreover, poor visibility due to heavy precipitation or fog, mist, smoke, etc. makes driving unsafe [10].
• 4. Road obstructions: Sometimes, trees or branches can partially or fully block roads. Moreover, there can be broken down vehicles on the roads which may require road users to brake abruptly. Apart from that, cones placed on the roads due to roadworks, animals crossing the roads, etc. can also lead to accidents. Although there are many other potential scenarios causing traffic hazards, these are the major causes of traffic incidents in different cities across the world.

What Is Intelligent Mobility?

Intelligent mobility is a buzzword nowadays, which encompasses the technological solutions for communication, control, and information processing in transportation [11]. With the growing number of vehicles on the road, traffic safety has become of utmost concern. Therefore, vehicles are now fitted with new technologies which can help avoid crashes and minimize the after-effects and therefore ensure road safety. Moreover, traffic management authorities are also being proactive in maintaining the smooth operation of traffic. They are adopting new technologies to inform road users about roadworks or other obstructions on the roads [12]. Nevertheless, traffic incidents are inevitable mostly because of human error or faulty vehicle parts [4]. To circumvent such situations, real-time traffic prediction models have been developed, which can forecast the incident duration and spread of congestion in advance so that road users can avoid getting stuck in traffic jams [13]. Thus, the overall congestion caused by the incidents can also be minimized.