RCOC Turning Warrants

Quick check for RCOC’s permit-guide envelopes for left-turn (median crossover) and right-turn (taper/lane) warrants.

Pick the movement below, enter the two-way ADT/AADT and the peak-hour turning volume, and the tool will compare the point to the agency’s reference lines.

Trucks count as two passenger cars for the left-turn branch only (per the permit guide PCU rule). Right-turn checks use the raw turning volume unless you note otherwise.

Example: 20% trucks → left turns × 1.20 for the warrant check. (Right-turn branch ignores this factor.)

Warrant Envelope Preview

Blue line = published left-turn envelope. The dot animates to your point (green when allowed, red when prohibited) after you hit "Check warrant".

Left-turn data is the RCOC permit-guide envelope (3,000–28,000 vpd). Right-turn data reflects the deceleration-lane/taper guidance you shared. The tool linearly interpolates between published points.

References

Source: Road Commission for Oakland County (RCOC) Permit Guide table for permitting left turns without a left-turn lane.

The inputs should reflect the combined two-way daily volume for the corridor and the single peak-hour left-turn demand being evaluated.