Highway traffic through chattanooga came to a standstill for most of the afternoon.

And the tennessee department of transportation says it still not clear why a concrete railing came crashing down onto i-24 at the i-75 split.

Authorities have had to make some big decisions this afternoon as they try to re-open that part of the interstate.

News 12's angela moryan is there now with the latest.

Traffic conditions coming from atlanta have lessened.

Lieutenant john harmon says help from gdot and ghd recap: part of the i75 south fell around noon today.

A car coming from georgia hit the barrier.

The police say that the driver has non life threatening injuries.

The biggest impact has been the traffic.

I spoke with dean from freightways.

He said that this happened at a good time because it is the beginning omg a quarter.

He is urging truckers to take alternate routes.

Tdot says that expect to have this open by tonight news 12's ashley henderson was here as that story was developing this afternoon.

Tdot officials quickly arranged a news conference this afternoon....as they worked to restore traffic around the i- 24/75 split.

That railing not only blocked traffic...it damaged one vehicle and injured the driver during the 11:30 a.m.

Incident.

Traffic from all three directions was impacted as officials assessed the damage.

A news conference was called at mid-afternoon at a grassy area near the site of the incident.

Lt.

Danny jones cpd: "as one of the cars got here on scene, they located a blue vehicle that had actually run into the fallen piece of the bridge.

At that time we went ahead and administered first aide to the driver and then we transported the driver to the hospital."

That bridge was built in the 1950's...as the interstate highway system was just beginning.

The fabled i-24/75 split is a legendary bottleneck in the south....but a major change is in the works.

Joe deering, tdot regional director "then we're going to begin an emergency bridge repair.

As you guys probably know, we already have this interchange under construction for the design build that we're doing, we're reconfiguring the interchange here, so we're going to be calling on that contractor to ahead and do an emergency bridge repair, to get that bridge back open to two lanes."

Deering says that's going to happen late this evening or possible early tomorrow morning.

The split is has been the scene of hundreds of vehicle crashes over the years.

The cause of the falling concrete railing is not known yet....but a tdot spokesman stresses it was not a "collapse".

Deering in: "we're going to put the concrete barrier rail up to where you see the gap in the rail up there right now...and that will close it down to one lane up there."

Deering says the ramp to 75 south won't be open in both lanes until that work on a farbricated barrier is done in three to four weeks.

In chattanooga, ashley henderson, news 12 now.

Dean from freightways says that this is not uncommon to have infrastructure problems on heavily trafficked freight routes.

Reporting live, angela moryan news 12 now.

No injuries reported in a