Examples

What is the braking acceleration $(\frac{m}{s^2})$ of a vehicle which travels with $80k\frac{m}{h}$ speed on a $5\%$ uphill road section.

Hint: Friction coefficient is $0\mathrm{.}50$ and perception reaction time of driver is $2s.$

There two vehicles moving towards each other on a same lane of a road with $3\%$ gradient. First vehicle is going upwards with a speed of $70k\frac{m}{h}$ and second vehicle is going downwards with a speed of $100k\frac{m}{h}.$ Calculate the minimum distance $($m$)$ so that drivers of the vehicles notice each other and stops without collision.

Hint: Friction coefficient is $0\mathrm{.}40.$ Perception reaction time of first vehicle's driver is $3s,$ and perception reaction time of second vehicle's driver is $2s.$

A driver hit a pedestrian on a road section with a $6\%$ downhill gradient where the speed limit is $80k\frac{m}{h}.$ After this accident brake mark is measured as $110m.$ The distance between accident point and beginning of the brake mark is measured as $85m.$ According to these;

a$.$ Calculate the speed of the vehicle $(k\frac{m}{h})$ at the start of braking.

b$.$ Would the accident occur if the driver had followed the speed limit$?$

c$.$ Calculate the maximum speed $(k\frac{m}{h})$ in order to prevent this accident.

Hint: Friction coefficient is $0\mathrm{.}50$ and perception reaction time of the driver is $2s.$

$4.$ A driver overtakes a vehicle which is going in front of her$/$his vehicle with a speed of $60k\frac{m}{h}$ on a two$-$lane undivided road in $12s$ while there is no vehicle on the other lane. Calculate the speed of overtaking vehicle $(k\frac{m}{h}).$

Hint: $d=8+0\mathrm{.}3x$

$5.$ A driver overtakes a tractor which has speed of $20k\frac{m}{h}$ with a speed of $50k\frac{m}{h}$ on alignment section of a two$-$lane undivided road at night. When the overtake ends there is a $10m$ distance between overtaking vehicle and another tractor which is going on the other lane. Calculate the speed of the tractor which is going on the other lane for most unfavorable condition.

Hint: Headlight distance of the overtaking vehicle is $100m.d=8+0\mathrm{.}3xV$

$6.$ There is a vehicle moving on a horizontal curve which has a $400m$ radius with a speed of $100k\frac{m}{h}.$ Determine whether is it safe or not when there is no superelevation is applied.

Hint: ${}_e=0\mathrm{.}12,$ the distance between vehicle's wheels is $1\mathrm{.}50m$ and the height of the vehicle's gravity center is $0\mathrm{.}80m.$

$7.$ There is a vehicle moving on a horizontal curve which has a $1,000m$ radius with a speed of $120k\frac{m}{h}.$ Determine whether is it safe or not when there is a maximum $8\%$ superelevation is applied.

Hint: ${}_e=0\mathrm{.}09,$ the distance between vehicle's wheels is $1\mathrm{.}50m$ and the height of the vehicle's gravity center is $0\mathrm{.}80m.$

$8.$ The passengers are affected by a lateral acceleration of $1\frac{m}{s^2}$ in a bus that is going on a horizontal curve which has a $600m$ radius with a speed of $110k\frac{m}{h}.$ Calculate the value of superelevation at that moment.