One of the common questions that Tesla owners and enthusiasts have is whether autopilot can change speed based on the detected speed limits.
The answer is not straightforward, as it depends on several factors, such as the type of road, the region, the software version, and the settings.
In this article, we will explain how Tesla autopilot works with speed limits, what are the possible problems and solutions, and what are the best practices for using this feature.
How does Tesla Autopilot work with Speed Limits?
Tesla autopilot has two main components: Autosteer and Traffic-Aware Cruise Control (TACC).
Autosteer keeps the car in its lane and avoids collisions with other vehicles or objects. TACC adjusts the speed of the car according to the traffic flow and the speed limit.
The way TACC works with speed limits varies depending on whether the car is on a highway or a non-highway road.
On Highways
On highways, TACC does not adjust speed to the speed limit by default. It maintains the speed that the driver sets unless there is a slower vehicle in front or an obstacle.
The driver can manually change the speed by using the scroll wheel on the steering wheel or tapping the speed limit sign on the display.
Alternatively, the driver can enable a setting called “Speed Limit Warning” in the Autopilot menu, which will alert the driver when they exceed the speed limit by a certain amount (which can be adjusted from 0 to 15 mph or km/h).
However, this setting does not automatically slow down or speed up the car.
On Non-Highway Roads
On non-highway roads, such as city streets or rural roads, TACC can adjust speed to the speed limit if the driver has purchased either Enhanced Autopilot (EAP) or Full Self-Driving (FSD) packages.
These packages include a feature called “Navigate on Autopilot” (NOA), which can guide the car from one highway exit to another, including lane changes and turns.
NOA can also use GPS data and speed limit signs to adjust speed according to the posted limit. The driver can set an offset value (from -5 to +10 mph or km/h) that will be added or subtracted from the speed limit.
For example, if the speed limit is 40 mph and the offset is +5 mph, NOA will set the speed to 45 mph.
Why Tesla Autopilot Not Changing Speed & How To Fix?
NOA is not perfect and sometimes fails to detect or recognize speed limit changes.
This can happen for various reasons, such as poor visibility, incorrect GPS data, missing or damaged signs, or sudden changes in traffic conditions.
In these cases, NOA may either maintain the previous speed or revert to a default speed (which is usually 45 mph in the US).
Here are some of the possible problems and solutions for using NOA with speed limits:
#1. NOA does not read speed signs correctly
This can happen when:
1. The sign is obscured by trees, snow, dirt, or other objects
2. The sign is faded, broken, or vandalized
3. The sign is too far away or too close to the car
4. The sign has an unusual shape, color, or font
5. The sign has conflicting information with other signs
Solution
The driver should always monitor the display and intervene if necessary. The driver can also report a problem with a sign by pressing and holding down on it on the display.
#2. NOA does not use GPS data correctly
This can happen when:
1. The GPS signal is weak or lost
2. The GPS data is outdated or inaccurate
3. The GPS data does not match with reality
Solution
The driver should always monitor the display and intervene if necessary. The driver can also update their maps by connecting their car to Wi-Fi.
#3. NOA does not adjust speed for turns or intersections
This can happen when:
1. The turn or intersection is sharp or complex
2. The turn or intersection has no clear markings or signs
3. The turn or intersection has a different speed limit than the road
Solution
The driver should always monitor the display and intervene if necessary. The driver can also reduce their offset value or disable NOA for turns or intersections.
#4. NOA does not adjust speed for traffic conditions
This can happen when:
1. The traffic is slow or stopped
2. The traffic is fast or erratic
3. The traffic has different speeds in different lanes
Solution
The driver should always monitor the display and intervene if necessary.
The driver can also adjust their following distance or disable NOA for traffic conditions.
#5. NOA does not adjust speed for road conditions
This can happen when:
1. The road is wet, slippery, or icy
2. The road is bumpy, uneven, or damaged
3. The road has hills, curves, or bumps
Solution
The driver should always monitor the display and intervene if necessary.
The driver can also reduce their speed or disable NOA for road conditions.
#6. NOA does not adjust speed for local regulations
This can happen when:
1. The local speed limit is different from the national or regional speed limit
2. The local speed limit is variable or conditional
3. The local speed limit is enforced by cameras or police
Solution
The driver should always monitor the display and intervene if necessary.
The driver can also check the local speed limit before using NOA or disable NOA for local regulations.
#7. NOA does not adjust speed for personal preferences
This can happen when:
1. The driver prefers to drive faster or slower than the speed limit
2. The driver prefers to drive more aggressively or cautiously than NOA
3. The driver prefers to have more control or freedom than NOA
Solution
The driver should always monitor the display and intervene if necessary.
The driver can also customize their settings or disable NOA for personal preferences.
What are the Best Practices for Using NOA with Speed Limits
NOA is a helpful tool, but not a substitute for human judgment and responsibility.
The driver should always be aware of the road conditions and the settings and adjust them accordingly.
Here are some of the best practices for using NOA with speed limits:
1. Always keep your hands on the steering wheel and your eyes on the road
2. Always follow the instructions and warnings on the display and in the audio
3. Always be ready to take over at any time
4. Always obey the traffic laws and respect other drivers
5. Always update your software and maps regularly
6. Always report any problems or feedback to Tesla
Conclusion
Tesla autopilot can change speed based on detected speed limits in some situations, but not in others.
The driver should always be aware of the road conditions and the settings and adjust them accordingly.
Autopilot is a helpful tool, but not a substitute for human judgment and responsibility.
