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Safe Braking Distance & Time Calculator

Mobile-friendly web version of the "SafeBrakingDistance&TimeCalc" worksheet. Only red cells from the sheet are editable here.

Inputs

Brake Rate mphps

Acceleration Rate mphps

Grade %

Use negative for downhill (e.g., -2.5), positive for uphill.

V_initial mph

V_final mph

Results

Total Distance

– ft

Total Time

– s

Copy a link with these inputs

Breakdown & intermediate values

Effective decel (fps²)

–

Effective accel (fps²)

–

V_tolerance (fps)

–

V_init+ovsp×1.02 (fps)

–

Segment	Distance (ft)	Time (s)
Code recognition	–	4.5 or 18
Brake assurance	–	0 or 13.5
Runaway acceleration	–	2
Coast after runaway	–	2
Brake buildup	–	6
Braking to V_final	–	–
Safety percentage	–	—
2× overhang	18	—
Total	–	–

Safety % is applied only when V_initial is exactly 79 mph (15%), 59 mph (10%), or 45 mph (5%), matching the original sheet.

Formula mapping mirrors the Excel: D5/D7/K5/K7/M5/M7, I19, I21, I25, I27, I29, I31, I33, I36, I37, I39–I47. Units: mph→fps uses 1.47. Grade adjustment uses 0.2195·grade(%), with Excel-style ROUNDUP/ROUNDDOWN.