## 2 German Traffic Space Analysis
### Route
#### 2.2.1 Classification  
In order to classify the data as one of the three main classes, the Open Street Maps Database (OSM) was used. The OSM Database consists of nodes connected by ways. Each node contains information based on their GPS position. The information contains, for example, highway type, references to street names such as the A5 (Motorway 5), the known (permanent) speed limit, the number of lanes, the city this node belongs to and more. The most important pieces of information for this study were the different highway types that were included in the chosen route [30]:  
* **Motorway**: A restricted-access major divided motorway, normally with two or more running lanes plus an emergency hard shoulder. Equivalent to the freeway, Auto-bahn, etc. * **Motorway link**: the link roads (slip roads/ramps) leading to/from a motorway from/to a motorway or lower-class motorways, normally with the same motorway restrictions. * **Trunk**: The most important roads in a country's system that are not motorways. (Need not necessarily be divided motorways.) * **Trunk link**: the link roads (sliproads/ramps) leading to/from a trunk road from/to a trunk road or lower-class motorway. * **Primary**: The next most important roads in a country's system. (Often linking larger towns.) * **Primary link**: the link roads (sliproads/ramps) leading to/from a primary road from/to a primary road or lower-class motorway. * **Secondary**: The next most important roads in a country's system. (Often linking towns.) * **Tertiary**: The next most important roads in a country's system. (Often linking smaller towns and villages)  
Figure 1: Route from the University of Darmstadt (A) to the first section on the motorway (A to C), the Taunus (B to C), the route to Frankfurt am Main’s city center and back to the University in Darmstadt. Image from Google Maps. * **Unclassified**: The least important through roads in a country's system--i.e., minor roads of a lower classification than tertiary, but which serve a purpose other than access to properties. These often link villages and hamlets. (The word \"unclassified\" is a historical artefact of the UK road system and does not mean that the classification is unknown.) * **Residential**: Roads which serve as access to housing, without the function of connecting settlements. Often lined with housing. * **Service**: For access roads to or within an industrial estate, camp site, business park, car park etc. Can be used in conjunction with service =
* to indicate the type of usage and with access =
* to indicate who can use it and in what circumstances. * **Footway**: For designated footpaths, i.e., mainly/exclusively for pedestrians. This includes walking tracks and gravel paths. If bicycles are allowed as well, this can be indicated by adding a bicycle = yes tag. Should not be used for paths where the primary or intended usage is unknown. Use motorway = pedestrian for pedestrianized roads in shopping or residential areas and motorway = track if it is usable by agricultural or similar vehicles. * **Path** A nonspecific path. Use motorway = footway for paths mainly for pedestrians, motorway = bikeway for one also usable by cyclists, motorway = bridgeway for ones available to horses as well as pedestrians and motorway = track for ones which are passable by agriculture or similar vehicles. From these data, the three main road types (urban, country and motorways) were derived. Rural Roads
* The motorway type is either _footpath_, _path_, _residential_ or _service_. * The motorway type is either _primary_, _primary link secondary_, _tertiary_ or _unclassified_, and the speed limit is equal to or lower than \(50\,\mathrm{km}\,\mathrm{h}^{-1}\). * The motorway type is _trunk_ or _trunk link_, and the speed limit is equal to or lower than \(50\,\mathrm{km}\,\mathrm{h}^{-1}\) and the city is either _Frankfurt_ or _Darmstadt_.