Lorries and other heavy vehicles will be banned from travelling on Sharjah's roads during periods of fog. Sharjah Police issued the directive on Friday as part of their efforts to bolster road safety when visibility is low. Officials said drivers of such vehicles would be barred from internal and external roads until fog had cleared. Motorists who ignore the ruling will be fined Dh500 and have four black points placed on their licence. Morning commuters have been greeted by thick fog in recent weeks, prompting police to take action to reduce the risk of accidents. Abu Dhabi Police implemented a similar ban on heavy vehicles last month. The hazardous conditions have caused major disruption for drivers. Last month, one person died and eight others were injured in a 19-vehicle pile-up in Abu Dhabi as heavy fog blanketed the capital. Abu Dhabi Police said the accident was caused by drivers failing to take account of the poor visibility. The force has regularly cut speed limits on many roads to 80kph during bouts of foggy weather. Police announce speed changes on social media and on alerts sent by phone. "Sharjah Police called on heavy vehicle and truck drivers to fully adhere to the decision to prevent this category of vehicles from driving during fog, and to take precautions and caution for their drivers, by applying correct measures that achieve the safety of road users," read a police statement on news agency Wam.