Road-holding – also written as roadholding and road holding – (in French being called "tenue de route", in German "Beibehaltung der Spur"), is essentially determined by the ability of a

vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), wa ...

to stay on the

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of ...

and on a desired

trajectory A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete traj ...

motion In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...

, whatever the circumstances (in curves, on greasy, wet or low-grip ground, loaded or not, etc.) may be, but also by the degree of ease that a driver may sense in controlling it in an

emergency An emergency is an urgent, unexpected, and usually dangerous situation that poses an immediate risk to health, life, property, or environment and requires immediate action. Most emergencies require urgent intervention to prevent a worsening ...

situation. (Hereby, the laws of nature as a framework, including the

gravitation In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stron ...

field Field may refer to: Expanses of open ground * Field (agriculture), an area of land used for agricultural purposes * Airfield, an aerodrome that lacks the infrastructure of an airport * Battlefield * Lawn, an area of mowed grass * Meadow, a grass ...

of the planet

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

as well as the phenomenon of

inertia Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...

, are tacitly assumed as given.) In the above context, the straight-line stability of a vehicle – which is concomitant with its ability to stay on a desired trajectory of motion – necessitates a certain degree of

understeering Understeer and oversteer are vehicle dynamics terms used to describe the sensitivity of a vehicle to steering. Oversteer is what occurs when a car turns (steers) by more than the amount commanded by the driver. Conversely, understeer is what occu ...

. The capability to smooth down the Road surface#Surface deterioration, road imperfections, affects both the comfort and the road-holding of a vehicle. To improve comfort in this regard means, basically, to limit the vertical acceleration wikt:fluctuation, fluctuations of the vehicle body and hence of passengers. To improve road-holding means, among other things, to limit the fluctuations of the vertical force that each tire exchanges with the road. Therefore, Conceptual model, modeling and simulation using realistic Suspension (mechanics), suspension-damping models, taking the vehicle tires into account, offer a straightforward opportunity for road-holding improvement of vehicles. Optimization techniques for this purpose are also known. The application of Inerter (mechanical networks), inerters is a very new possibility in this regard, although this technology is more destined to race cars than to ordinary vehicle applications. As a more sophisticated means for improving road-holding, active suspension – involving sensors, actuators and microcontrollers – may also serve. For vehicle speeds above approximately 40 meters per second, the effects of aerodynamic forces at an automobile (that is not designed in a too odd manner) tend to become sensible for its road-holding.Doniselli, C. et al.: ''Aerodynamic effects on ride comfort and road holding of automobiles.'' In: ''International Journal of Vehicle Mechanics and Mobility.'' Vol. 25, Issue Suppl. 1, pp. 99-125, 1996. Beyond what has been previously mentioned, electronic stability control, if being present on a vehicle and properly tuned, will have a stabilizing influence on the trajectory of motion and accordingly an improving effect on road-holding of that vehicle.

References

Vehicle dynamics

See also

References