I am thinking about starting to commute to college by a road bike. My commute is 30 mile round trip. I found a couple of bikes on craiglist, but since I am not an expert, I need some advice on which one to choose.

The bikes are :
2007 Trek 1000 road bike
Trek 1000 road bike
Trek alpha 1.1 road bike
https://houston.craigslist.org/bik/4417901637.html
TREK ALPHA 1.2 road bike w/shimano & bontrager
2011 Trek 1.2 58CM

I was looking to spend up to $450, but I am willing to spend $200 more. I will attach a rack to it to put my backpack on. I am 5'10'' and I live in Houston, so my ride will be on a flat area.

Thanks for your help.

Those look like racing type bikes, going by the pics (can't really tell, since I can't enlarge the pics). What you're looking for is, is a touring/commuter bike

What I would suggest is, is to check out a local bike store. Talk to the staff members about what you're looking for, as well as how much you're willing to spend, equipment included. A reputable store will find and properly fit a bike for you. Get an actual rack, not a seat post one for better load carrying capacity. Also, a handlebar mount mirror (Supercycle has a really good one) and lights, as well as a hi-vis vest if you have to ride after dark. I also recommend fenders. Not the seat post ones, but actual fenders.

This is only very general list, but it's a start.

GIANT AVAIL ROAD BIKE

https://houston.craigslist.org/bik/4415785177.html

Any of those bikes look suitable provided they fit. They all appear to accept full fenders. I don't know what facilities you have available for locking your bike on campus but around here, theft is a significant issue so I would go with the least expensive, ugliest bike available. I commute about 40mi roundtrip to work and look for a bike that I can get into a reasonable aero position in order to minimize the work required.

I commuted for many thousands of happy miles on a Trek 1000.

The 1.1 is a newer version, and the 1.2 has slightly better components.

Mine took full fenders and a rear rack just fine, but when loaded with more than 30 pounds or so in back, the tail sort of wags the dog. Just fine for commuting. Grocery-getting was the problem.

When choosing between the ones above, the 54 is probably too small. The 58 might be a smidge big, but workable. Otherwise, give extra points for puncture-resistant tires. If none of them are so equipped, make them your first upgrade. Nothing says "loser" quite like being late for work because you had a flat.

Thank you for your response. I am more interested in the 2 trek 1000, since they fit my budget and also this is my first time buying a bike so I am not looking to buy a higher end bike. Which one would you recommend, the 2007 Trek 1000 road bike or the Trek 1000 road bike .

College Campuses are theft magnets for bikes. Make certain that you get a nice U-Lock!

Get the cheaper bike of the two!

Can't say since neither seller has told us the size. If it doesn't fit, you shouldn't buy it.