I-35 in Austin splits into an upper deck and a lower deck. The split is confusing to drivers not familiar with it, and accidents are frequent.
 
One writer (below) states that the lower deck is nicknamed “Suicide Alley (or something to that effect, depending on who you talk to).” Although the lower deck is known to be dangerous, it does not appear to have any one particular commonly used nickname.
   
   
IndoMeet Travel - Austin
I-35 has no loop that circumnavigates the city, so watch out for aggressive, confused drivers. Also, keep your eyes open for the upper deck/lower deck split between Airport Blvd and Martin Luther King Jr Blvd; it’s confusing, and accidents occur there frequently. Drivers going through Austin without stopping, or those who wish to avoid the chaos of the lower deck, should use the right two lanes as the deck split approaches, in contrast to other cities where through traffic uses the left lane. On the northbound side, traffic entering I-35 at Martin Luther King Jr Blvd goes directly to the upper deck.

Out-of-towners be warned: on-ramps on I-35, especially the lower deck, are very short. 
 
Fodor’s
Author: gordiemonster
Date: 04/03/2003, 01:42 pm
I live in Austin as well and agree that I-35 is misery—it’s a split level freeway downtown and the lower deck is quite dangerous. You have about 50ft to merge as 18-wheelers roar past you. 

Dallas Fort Worth Urban Forums
rjlevins
04-16-2005, 11:29 AM
I-35 Split in Austin: Constant 18-wheeler accidents on the lower deck. An accident caused by the split shuts down the entire highway…one night it took me an hour and a half to move about a mile because the entire highway was diverted onto the service road. People who are not used to the area get confused on which part to take if they need to exit. Common sense says that the left side of the road would be the through traffic, but then they realize that that side dips down. When the roads merge again, people try to cut over real fast to exit for downtown and cause even more accidents. To make matters worse, there is a hill that you can’t see over right as the roads are merging, so when traffic is at a standstill right on the other side of the hill, accidents are bound to happen.

voodoodragon (Livejournal)
Irish (voodoodragon) wrote,
@ 2005-04-17 06:15:00
(...)
For those of you who read this and don’t live in Austin, there’s a part of I-35 that splits into Upper and Lower Decks, 2 lanes each. The Upper Deck is like an expressway to bypass the exits and entrances from Austin. The Lower Deck is nicknamed Suicide Alley (or something to that effect, depending on who you talk to). A far as I can tell, this is due to the almost complete lack of a shoulder before the cement barriers, very short entrance ramps, and bad signage for exits. It’s a marvel of stupidity, but that’s common in Austin.