To know how many meters you travel per second, multiply the speed by 1000. You then have the number of meters per hour. 1 hour has 3600 seconds. Divide the result by 3600 and you know how many meters you travel per second. Formula: Meters per Second =Speed*1000/3600.
It can also be even simpler!
Divide the speed by 4. To this result add 10 percent of this result. The outcome is not exactly the same,but you are not too far off.
Example: you are driving 100 km/h. 100/4 = 25. Then you take 10 percent of 25, which is 2.5. You add up the 2 outcomes: 25 + 2.5 = 27.5 meters per second.
The chart below lists different speeds in km/h.
2nd column: rounded the exact speed.
3rd column: the speed according to the simple calculation.
4th column: the minimum tracking distance of 2 seconds.
5th column: average Reaction Road. This assumes 1 second of driver startle response.
6th column: Average braking distance on a dry road surface.
7th column: average braking distance on a wet road surface.
8th column: stopping distance on a dry road surface.
9th column: stopping distance on a wet road surface.
The following constants were used in all calculations:
Average braking deceleration: 7.5 m/s2
Clearance coefficient dry road surface: 1.0
Wet road clearance coefficient: 1.4
If you think math is great then you can calculate your own collision speed. The formula for this is: Root from :√(2*average braking deceleration)*(stopping distance driven speed – stopping distance prescribed speed)
Example: the allowed max speed is 30 km/h. You yourself are driving 50 km/h. Now suddenly an obstacle appears (crossing child or cyclist). At a speed of 30 km/h, you stop just in front of the obstacle. At 50 km/h, you have no braking distance and you hit the obstacle at 50 km/h. If you drive 40 km/h, your impact speed is still 35 km/h!
| km/h | m/s | quickly calculated m/s | 2 sec tracking distance | response road | Brake path dry | Brake path wet | Stop distance dry road surface | Stopping distance wet road surface |
|---|---|---|---|---|---|---|---|---|
| 10 | 2,8 | 2,75 | 5,5 | 2,78 | 0,51 | 0,72 | 3,29 | 3,50 |
| 20 | 5,6 | 5,5 | 11 | 5,56 | 2,06 | 2,88 | 7,61 | 8,44 |
| 30 | 8,3 | 8,25 | 16,5 | 8,33 | 4,63 | 6,48 | 12,96 | 14,81 |
| 36 | 10 | 9,9 | 19,8 | 10,00 | 6,67 | 9,33 | 16,67 | 19,33 |
| 40 | 11,1 | 11 | 22 | 11,11 | 8,23 | 11,52 | 19,34 | 22,63 |
| 50 | 13,9 | 13,75 | 27,5 | 13,89 | 12,86 | 18,00 | 26,75 | 31,89 |
| 60 | 16,7 | 16,5 | 33 | 16,67 | 18,52 | 25,93 | 35,19 | 42,59 |
| 70 | 19,4 | 18,25 | 36,5 | 19,44 | 25,21 | 35,29 | 44,65 | 54,73 |
| 72 | 20 | 19,8 | 39,6 | 20,00 | 26,67 | 37,33 | 46,67 | 57,33 |
| 80 | 22,2 | 22 | 44 | 22,22 | 32,92 | 46,09 | 55,14 | 68,31 |
| 90 | 25 | 24,75 | 49,5 | 25,00 | 41,67 | 58,33 | 66,67 | 83,33 |
| 100 | 27,8 | 27,5 | 55 | 27,78 | 51,44 | 72,02 | 79,22 | 99,79 |
| 108 | 30 | 29,7 | 59,4 | 30,00 | 60,00 | 84,00 | 90,00 | 114,00 |
| 110 | 30,6 | 30,25 | 60,5 | 30,56 | 62,24 | 87,14 | 92,80 | 117,70 |
| 120 | 33,3 | 33 | 66 | 33,33 | 74,07 | 103,70 | 107,41 | 137,04 |
| 130 | 36,1 | 35,75 | 71,5 | 36,11 | 86,93 | 121,71 | 123,05 | 157,82 |
| 140 | 38,9 | 38,5 | 77 | 38,89 | 100,82 | 141,15 | 139,71 | 180,04 |
| 144 | 40 | 39,6 | 79,2 | 40,00 | 106,67 | 149,33 | 146,67 | 189,33 |
| 150 | 41,7 | 41,25 | 82,5 | 41,67 | 115,74 | 162,04 | 157,41 | 203,70 |
| 160 | 44,4 | 44 | 88 | 44,44 | 131,69 | 184,36 | 176,13 | 228,81 |
| 170 | 47,2 | 46,75 | 93,5 | 47,22 | 148,66 | 208,13 | 195,88 | 255,35 |
| 180 | 50 | 49,5 | 99 | 50,00 | 166,67 | 233,33 | 216,67 | 283,33 |
| 190 | 52,8 | 52,25 | 104,5 | 52,78 | 185,70 | 259,98 | 238,48 | 312,76 |
| 200 | 55,6 | 55 | 110 | 55,56 | 205,76 | 288,07 | 261,32 | 343,62 |