ABSTRACT Today many vehicles are being developed with advanced computing and sensing technologies. These new technologies have contributed in enhancing driving safety and convenience. As an example, the Adaptive Cruise Control (ACC) can automatically adjust the vehicle speed to driver's set speed and maintain the driver-requested headway distance to the lead vehicle. In this paper, we further consider the automatic control of speed according to the road attributes, e.g., the speed limit and curve of the road. Two new features, ‘speed limit follower’ and ‘curve speed control’ algorithms, are proposed in this paper. These new features communicate with the conventional ACC system and control the vehicle speed while traveling across different curved roads and speed limit zones. These new features were developed as an independent function, so they can be integrated with any other existing ACC systems. The key enabler for these features is sensing the speed limit and the curvature of upcoming roads using the OnStar GPS and a digital Map. The speed planning algorithm determines the desired vehicle speed profile to provide smooth speed transition along the road curve and the speed limit changes. The vehicle control system regulates the speed of the vehicle according to the desired speed profile. The speed limit follower and the curve speed control algorithms are implemented into a test vehicle with the production cruise control module. The vehicle test results are provided at the end of the paper. INTRODUCTION The automotive industry has made considerable effort to enhance driving safety and convenience over past decades through autonomous and semi-autonomous driving features. The cruise control is one example of semi-autonomous driving features, which maintains the vehicle speed to the driver's set speed. Adaptive Cruise Control (ACC) [ 1] is an advanced feature with automatic adjustment of the vehicle speed to maintain a constant headway to a lead vehicle. Beyond the automatic longitudinal motion control, Lane Keeping Assist (LKA) systems [ 2,3] and Lane Centering / Changing (LCC) system [ 4,5] further reduce the driving burden. The Global positioning system (GPS) technology enables tracking of the vehicle location. Combined with the digital map technology, the speed limit and the curvature of the road can be accurately found. Road Speed limits are used to regulate the speed of the road vehicles. It is often utilized with an intention to improve road traffic safety and reduce the number of road traffic casualties from traffic collisions. Using this speed limit information, certain vehicles already available in the market inform the driver of exceeding the road speed limit. This paper further considers an active speed control, which adjusts the speed of the vehicle automatically to follow the current road speed limit. In addition to the road speed limit, there are certain situations that the vehicle has to be driven with a slower speed than the driver's requested speed. For example, if driver sets the cruise speed higher than the road speed limit and the vehicle is approaching to a tight curve, the proposed curve speed control adjusts the vehicle A Unified Framework of Adaptive Cruise Control for Speed Limit Follower and Curve Speed Control Function2013-01-0618 Published 04/08/2013 Jin-Woo Lee General Motors Company Shilpa Prabhuswamy Danlaw Inc. Copyright © 2013 SAE International doi:10.4271/2013-01-0618Downloaded from SAE International by University of British Columbia, Thursday, August 02, 2018speed to properly negotiate the curve. Combining with the automated lateral control features, e.g., the LKA and the LCC system, the curve speed control provides enhanced driving safety, particularly when the steering actuator cannot achieve these features' steering torque commands. In this situation, the vehicle speed needs to be reduced to negotiate a tight curve before the vehicle enters the curved road. This paper proposes a framewo