# Environmental-Based Speed Recommendation for Future Smart Cars +
## 3 Proposed Approach
### On-Route Information  
As shown previously, the proposed approach can estimate the road class solely based on information about the weather conditions. However, weather conditions alone cannot provide any additional information about physical characteristics of the road. For that reason, on-route information is introduced as a new source of information that offers knowledge about the structure of the road. A vehicle connects to a cloud service and, for each intermediate point of the route, it transmits the current geographical coordinates. Then, it receives a variety of attributes concerning road characteristics: speed limit, soft or hard turns, highway exits, bridges, etc. The information about the nominal speed is classified into eight regions: (i) R\({}_{0}\): \(>\)120 km/h; (ii) R\({}_{1}\): 100-120 km/h; (iii) R\({}_{2}\): 90-100 km/h; (iv) R\({}_{3}\): 65-90 km/h; (v) R\({}_{4}\): 50-65 km/h; (vi) R\({}_{5}\): 30-50 km/h; (vii) R\({}_{6}\): 10- 30 km/h; and (viii) R\({}_{7}\): \(<\) 10 km/h. Additionally, from on-route information, we extract intermediate way points where the car needs to reduce its speed. At these points, the driver can potentially experience loss of vehicle control. We define as _Points of Interest (PoI)_ the intermediate points of a route that force a vehicle to change its speed, considering the road characteristics and the vehicle dynamics. In that sense, Pols include every single point that nominal speed changes: turns, ramps, highway exits, including the vehicle type characteristics as well. For instance, a turn can be light or sharp, so that the nominal speed to pass over that turn will be slightly different for different types of vehicles (e.g., trucks or a passenger car). In order to be comprehensive, on-route information is extracted for both urban and highway drive scenarios. As an example, consider that a vehicle starts its route from a point A and finishes at point B. The proposed framework captures the Pols and notifies the driver to adjust the speed of the car according to the nominal speed. Figure 2a shows a scenario of utilizing on-route information during an urban trip. The route that is shown in Figure 2a depicts a route in Southern Illinois University Campus in Carbondale, IL. Figure 3a illustrates the _PoI_ that were captured for the presented urban drive scenario (red bullets). In fact, for the presented route, three Pols were captured: (i) a traffic light; (ii) a stop sign; and (iii) a pedestrian crosswalk. It is evident that all the aforementioned points are common characteristics of urban driving and require a significant change in vehicle speed. Another useful piece of information that can be retrieved from on-route information is the elevation of the current position of a vehicle. Based on the longitude and the latitude of each intermediate point of a route, we can retrieve elevation information for that particular point. Elevation can be useful to extract more PoIs, since it can be a factor which changes the nominal speed of the vehicle, due to special weather conditions or road characteristics (road grade). For example, it is more likely to get snow or ice in higher elevations due to local weather characteristics. It can also contribute to extracting the incline, since a sudden change in the road's grade can cause a major change in speed. Figure 2b depicts a highway driving scenario. The route starts from Carbondale, IL, USA and ends at Atlanta, GA, USA. For that given route, the nominal speed limits and the Points of Interest are determined. Since this route is much longer than the urban scenario presented in Figure 2a, it is worth depicting the Points of Interest in correlation with the elevation. In fact, for that particular route, the terrain changes drastically, as it is illustrated in Figure 3b. Since most of the route consists of highway and freeway segments, the recommended speed for the majority of the trip is the highway speed limit. However, it is worth mentioning that in Figure 3b we can observe many color changes, which reflect the recommended speed.