Thousands of commuters endured a wet weather washout as heavy rain left railways and roads impassable.
The two main routes north out of Sussex for London-bound commuters were closed for about four hours during yesterday’s rush hour, leaving tens of thousands of people unable to get to work.
Problems on the rail network were still going on as The Argus went to press last night.
Road policing teams said the county received more than eight times the predicted rainfall, with 40mm of rain falling overnight.
Combining with already saturated ground, the result was traffic chaos.
More heavy showers are expected tonight but then the county can expect a few days of relief from the rain.
The Highways Agency closed the A23 between Pease Pottage and Bolney at 3.30am yesterday, creating tailbacks of more than five miles as drivers attempted to find back routes through country roads.
The northbound carriageway reopened at 9.40am after gulley suckers cleared away the excess water and the southbound carriageway opened 50 minutes later.
Sergeant Stewart Goodwin, of Sussex and Surrey Road Policing Unit, said that an action plan was in place to deal with any further rain in the next 48 hours.
He added a warning that standing water could be “deceptive” and advised motorists that they drove through it at their own risk.
On the trains, Network Rail closed the track between Three Bridges and Haywards Heath at 6.30am because of flooding in the Balcombe Tunnel.
Trains reopened at 10.15am, although the service was still struggling with delays of up to 45 minutes for most of the morning.
Replacement buses were affected by flooding on local roads, so passengers for London were advised to travel via Barnham or Hastings.
Flooding at Lingfield also closed trains between Hurst Green and East Grinstead and flooded roads meant no rail replacement buses could run either.
One Argus reader said their normal 35-minute commute between Portslade and Crawley took them two hours and 50 minutes.
Caroline Lucas, Green MP for Brighton Pavilion, said she had arranged a meeting with Network Rail in the wake of the flooding.
Elsewhere, firefighters were busy in the north of the county helping pump floodwaters away from homes in Gossops Green and Broadbridge Heath as well as a hotel in Copthorne Common Road.
Manor Green College in Crawley closed because of nearby flooding as Gatwick Road in Crawley, Kerves Lane in Horsham, the A264 Horsham Bypass and Friars Rookery in Three Bridges were all shut.
A West Sussex County Council event for beneficiaries of a flood prevention fund in Crawley was also cancelled because of flooding.