Results for area 12.3 System parameters
the lateral clearance of a target vehicle is defined as the lateral distance between the side of the subject vehicle and the near side of a target vehicle.
lateral distance between the longitudinal centerlines of a subject vehicle (SV) and a target vehicle (TV), measured as a percentage of the width of the SV, such that if the centers of the two vehicles are aligned, the value is zero
value of pre-collision urgency parameter (PUP), relative to an expected collision, for which FVCMS initiates a countermeasure
time needed for a vehicle approaching the intersection at a speed of v to travel the distance, X, from its current location to the stop line
estimated time that it will take a target vehicle to collide with the subject vehicle assuming the current closing speed remains constant
NOTE Time to collision can be estimated by dividing a target vehicle’s rear clearance by its closing speed. This definition applies to target vehicles in the rear zones only.
calculated time to lane departure
NOTE 1 to entry: For example, the most simple calculation method of this time (TTLC) is to divide lateral distance (D) between the predetermined part of the vehicle and the lane boundary by rate of departure (V_depart) of the vehicle relative to the lane. (TTLC = D/V_depart)
optical radar reflectivity of the target, which is defined as the radiated intensity towards the receiver (Iref - W/sr) measured at target level, immediately after the reflection; divided by the intensity of irradiation received from the transmitter (Et - W/m2) measured at target level, immediately before the reflection
NOTE 1 to entry: The units for RCTT value are in m2/sr.
value of PUP, relative to an expected collision, for which initiation of a specific countermeasure shall be required
the minimum subject vehicle (SV) speed for which FVCMS must be capable of activating a countermeasure
distance from the forward vehicle's trailing surface to the subject vehicle's leading surface
average distance between the front of one vehicle and another in a continuous traffic flow
NOTE This parameter is inversely proportional to the density of traffic.
the minimum deceleration that, if constant, would enable the subject vehicle to match the path velocity of the target vehicle without contacting the target vehicle and thus prevent a collision
NOTE Consideration of the target vehicle deceleration DTV is optional. When not used, it shall take a value of zero.
real-time parameter that signifies the urgency of a potential future collision
relative velocity between the subject vehicle and the detected obstacle, regardless of whether one or both is/are stationary or moving
time that it will take a subject vehicle to collide with the target vehicle assuming the relative acceleration between the subject vehicle (SV) and target vehicle (TV) remains constant
the adjacent zones are the zones to the left and right of the subject vehicle
NOTE 1 to entry Note that the adjacent zones are intended to cover the lanes adjacent to the subject vehicle. However, the position and size of the adjacent zones are defined with respect to the subject vehicle, and are independent of any lane markings.
difference between the longitudinal velocities of the subject vehicle (SV) and the target vehicle (TV), vr(t), given by the equation; equivalently the rate of change with respect to time of the distance between the two vehicles
NOTE A positive value of relative velocity indicates that the target vehicle is moving faster than the subject vehicle, and that the distance between them is increasing with time vr (t)= vTV (t )−vSV (t).
specific three-dimensional space around the vehicle, which is divided into rear and front corner m.r., front, rear-1 and rear-2 m.r
NOTE The covered monitoring ranges depend on the intended use of the system.
the subject vehicle’s overtaking speed is defined as the difference between the subject vehicle’s speed and the target vehicle’s speed when the subject vehicle is overtaking the target vehicle
NOTE A positive overtaking speed indicates that the subject vehicle is moving faster than the target vehicle.
component of subject vehicle’s approach velocity at a right angle to the lane boundary
the rear clearance of a target vehicle is defined as the distance between the rear of the subject vehicle and the front of the target vehicle as measured along a straight line, or optionally, as estimated along the target vehicle’s estimated path
NOTE This definition applies to target vehicles in the rear zones only.
the rear zones are the zones which are behind and to the sides of the subject vehicle
NOTE The rear zones are intended to cover the lanes adjacent to the subject vehicle. However, the position and size of the rear zones are defined with respect to the subject vehicle, and are independent of any lane markings.
the coverage zone is defined as the entire area to be monitored by a LCDAS; in other words, a target vehicle located within the coverage zone will be detected by the system
NOTE 1 to entry A system’s coverage zone will consist of a specific subset of the following zones: left adjacent zone, right adjacent zone, left rear zone, and right rear zone.