Fares are related to the supply & demand of drivers so this means at peak times when there is a high demand from customers the fares may increase. This may happen for short periods for example rush hour and busy times at weekends and once more drivers become available the fares will go back to normal. The app will always display to most accurate price including any surcharge at the time of requesting your trip. If there is any further increase once your trip has commenced you will still only be charged what you were quoted at the start of your trip.