How Average Speed is Calculated in Mixed Sections (Urban + Rural)

Example with the section on Road I-5: Polski Trambesh → Polikrayshe

When a toll section includes both rural road and passage through populated areas, the permitted average speed for the entire section is calculated by summing the time to travel each subsection at the respective limit. Then the total distance is divided by the total time.

Rule: The permitted average speed for the entire section is the highest possible average speed obtained by observing the local limits (without accounting for acceleration/deceleration time).

Steps (how to calculate it)

Divide the section into subsections: rural segment → settlement entrance → inside settlement → exit → next rural segment, etc.
Assign a limit for each subsection: e.g. 90 km/h rural (cars), 80 km/h (trucks), 50 km/h in settlement (unless indicated otherwise).
Calculate time for each subsection:
t_i (min) = (d_i (km) / v_i (km/h)) * 60
where d is the distance (km), v – permitted speed (km/h). Convert t to minutes.
Sum the times for all subsections → get the total time for a car (t_car) and for a heavy vehicle (t_truck).
Average speed for the entire section:
v_avg (km/h) = D_total (km) / t_total (hours)

Example: Polski Trambesh → Polikrayshe (total ≈ 21 km)

The section passes through three settlements – Radanovo, Petko Karavelovo, Kuttsina – and includes alternating rural/urban segments.

Subsections and Estimated Times by Limits

The rows below use real measurements/calculations. For urban parts, time for cars and heavy vehicles is the same (common limit), for rural – different (90 km/h for cars; 80 km/h for trucks/buses).

Start camera → Radanovo entrance — Distance: 2.9 km | Time (cars): 1.94 min | Time (trucks): 2.18 min
Inside Radanovo (entrance → exit) — Distance: 1.2 km | Time (cars): 1.44 min | Time (trucks): 1.44 min
Radanovo exit → Petko Karavelovo entrance — Distance: 3.5 km | Time (cars): 2.34 min | Time (trucks): 2.63 min
Inside Petko Karavelovo (entrance → exit) — Distance: 1.3 km | Time (cars): 1.56 min | Time (trucks): 1.56 min
Petko Karavelovo exit → Kuttsina entrance — Distance: 2.1 km | Time (cars): 1.40 min | Time (trucks): 1.58 min
Inside Kuttsina (entrance → exit) — Distance: 1.7 km | Time (cars): 2.04 min | Time (trucks): 2.04 min
Kuttsina exit → Polikrayshe entrance — Distance: 7.9 km | Time (cars): 5.27 min | Time (trucks): 5.93 min
In Polikrayshe (entrance → end camera) — Distance: 0.35 km | Time (cars): 0.42 min | Time (trucks): 0.42 min

Total distance: 21 km

Total time:

Car: 16.41 min (≈ 0.2735 h)
Heavy vehicle: 17.78 min (≈ 0.2963 h)

Permitted average speed for the entire section:

Car: ≈ 76.6 km/h
Heavy vehicle: ≈ 70.7 km/h

This means that if you maintain an average of around 76 km/h (cars) or 70 km/h (trucks) for the entire 21 km section, observing local limits by subsection, you'll be within the permitted range for the section.

Why is that?

If the entire road is 20 km with a limit of 90 km/h, but between the 10th and 17th km passes through a settlement with 50 km/h, then for those 7 km the calculation uses 50 km/h, not 90 km/h. Thus the total time increases, which reduces the permitted average speed for the entire section.

Practical Tips

Plan ahead: review the subsections along your route in advance (see our map).
Watch notifications: TollTracker alerts you when entering/exiting and shows your current average speed against the limit.
Don't rely on "making up time": high speed outside a settlement doesn't compensate for speeding in an urban zone from an average time perspective.