This can be prevented by taking care in the placement and alignment of the light. Generally speaking, if you can see a lights filament or source from a reasonable distance then the light is not well shielded. The glare from an unshieded fixture can compromise visibility and increases the chance for accidents. Bright glare can also produce high contrast shadows. These shadows actually become cooridors of darkness that can become hiding places for potential criminals.
Excessive glare can make driving difficult and light clutter can cause distraction.
For safety reasons every effort should be made to establish quality lighting on and near heavily traveled roads. Billboards and outdoor signs are designed to attract our attention. Often these are lit up with bright flashing lights. These light sources add considerably to the overall light pollution. A night time aerial view of a city reveals how much energy we waste by using unshielded lights.