The 9th International IEEE Conference on Intelligent Transportation Systems (ITSC 2006)
September 17-20, Toronto, Canada
Collision avoidance systems (CAS) are an emerging automotive safety
technology that assists drivers in avoiding
collisions. They monitor the dynamic traffic and vehicle information in
real time and assess the current threat level to decide if warnings
should be issued to the driver or automatic braking is needed to avoid
collisions. Several measures have previously been defined for threat
assessment with various warning and overriding algorithms proposed.
A new threat assessment measure, time-to-last-second-braking
is proposed in this paper and its advantages over previous measures are
discussed. It directly quantifies the danger or threat level of the
current dynamic situation objectively as well as assesses the urgency
level for the required evasive action, e.g., braking.
It is in agreement with human natural judgment of the urgency and
severity of threats. Furthermore, new warning and overriding criteria
are proposed based on the new Tlsb measure,
providing more appropriate warning
and more effective override timing.