• Advanced Driver Assistance Systems
  • Automated Driving Systems
  • Automated Vehicles

Predictive Speed Control Is Becoming More Widespread

Sam Abuelsamid
Nov 30, 2022

Guidehouse Insights

Back in October 2017, as I was going for my first drive in a Cadillac CT6 with Super Cruise, I experienced an unusual phenomenon. As the car was approaching a curve in the highway in hands-free mode, it began to slow down and then resumed its original speed as the road straightened out. I wasn’t expecting it, but the predictive speed control behaved exactly as the engineers intended. Five years later, predictive speed control is finally starting to become more commonplace and could prove to be a real benefit as part of a broader trend toward proactive safety.

In recent weeks, both Ford and Toyota have announced the addition of predictive speed control to the driver assistance suites on upcoming models. Ford initially announced that it would begin rolling out an updated version of its hands-free Ford BlueCruise / Lincoln ActiveGlide system featuring this capability, and the company is now adding it to the refreshed 2023 Ford Escape as well. Toyota is including predictive speed control as part of the Toyota Safety Sense 3.0 suite in its flagship Crown sedan. Other manufacturers, such as GM and Mercedes-Benz, have had this feature for several years.

The GM implementation of predictive speed control uses the high-definition maps that enable the geofencing of Super Cruise as a long-range sensor, looking out about 2.5 km. Since the maps contain detailed information about road topography and curvature, Super Cruise can calculate what a safe speed through the curve would be without the risk of losing traction. If the set speed exceeds the maximum safe speed, Super Cruise gently slows the vehicle as it approaches the curve and then automatically resumes the previous speed as the car exits the curve.

Super Cruise was originally designed to only operate on divided highways, although the available roads have since tripled to encompass more than 400,000 miles. When Mercedes-Benz launched its system in 2018, the predictive speed control operated whenever navigation and cruise control were active. If the vehicle was approaching an intersection where the route called for a turn, it would automatically slow down to a suitable speed and then resume after the driver had completed the turn. It also adjusted for curves and roundabouts.

Ford’s new system also uses maps as a look-ahead sensor to make speed adjustments when using BlueCruise, ActiveGlide, or conventional adaptive cruise control. The Toyota system apparently does not use map data, relying only on the forward-facing camera to detect curves. While this approach may be less costly, it is also likely to have more limited ability to determine the appropriate speed for the curve, although in an initial evaluation in daylight and good weather conditions, it worked smoothly and seamlessly.

In general, the shift toward using an array of data—from maps to connectivity to real-time sensing—to better understand the driving context is likely to provide some significant safety improvements. Early generation driver assistance features such as antilock brakes and even stability control were purely reactive systems that detected impending vehicle instability, using wheel speed, inertial sensors, and driver input signals to respond by modifying brake and engine controls. While this could help drivers maintain control of the vehicle, it could not always avoid collisions. The new generation of advanced driver assistance systems increasingly look outward from the vehicle to detect potentially dangerous scenarios and intervene earlier, providing a better chance of preventing crashes.