I live about 6 miles outside of town. I can either take the wide shoulder of Interstate 17, or a forest service road that hooks up with SR 89A. The problem with 89A is that there is no shoulder at all and I'd have to be on it for about a half mile. It would also add an extra mile or so to my commute. What do you guys think?

How much traffic is there on SR 89A? It can be quite peaceful and safe or extremely nerve-wracking. The worst kind of road to bike on is a fast narrow country road with only one lane in each direction and a constant stream of traffic both ways. Even half a mile might seem long under those conditions. However, if there is not much traffic, it can be a nice option.

How many interchanges/merges/diverges do you have to cross on the interstate and how busy are they generally?

Things to consider:

Are you allowed on to the Interstate there?

Is either leg of your commute when it is dark?

How well lit is either route? 89A probably has none...

What's the traffic like on 89A? Two lane, I assume...

There was quite a bit of traffic on 89A the couple of times that I've been on it, but I've never been on it early in the morning. You're right chephy, that half mile seems long because it is up hill and I'm up against a guard rail for part of it.

On the I-17, I would be able to get off on the first exit I come to and ride the next two miles on a bike path into town. But it would be a lot faster to stay on the Interstate and get off at the second exit.

Yes, it is legal to ride on the Interstate here.

No, none of my commute will be in the dark (I'm hoping), and neither road is lit at all.

89A is two lane with almost no shoulder and the speed limit is 55 I believe.

Thanks for the responses guys! I might have to take a day off and ride up to 89A to study the traffic at the time I might be riding on it.

If you don't have to actually cross I-17, it sounds like that would be safer, except possibly if 89A's traffic is much lower. The difference between 55 mph and 65 mph isn't much, and you've got a wide shoulder to ride on on the interstate.

I'm surprised cycling on the interstate is legal, though. In most places it is illegal to walk or ride bicycles on interstate highways.

Typically it is legal where no other reasonable routes exist. That usually is in the not-too-densely populated places. Apparently, there are long and quite pleasant stretches of interstate along the U.S. West Coast where cyclists are allowed, and lots of touring cyclists use them.

So I'm looking at the area on google maps. The vegetation looks pretty darn thin there. If it were my ride, I would not take either road. I would stay off-road the whole time.

I think of commuting this way: once you get splattered by a car, you are dead and that's that. If humanity had a better grasp of risk, they would take the safest routes possible all the time. I would rather ride a longer, rougher route and live to see my grandchildren grow up.

I would save up about $1000, get a nice classic hard tail mountain bike like a Kona Cindercone or a Specialized Rockhopper or something and go for it.

It is illegal for pedestrians to walk on the Interstate, but there's a sign as you're getting on the I-17 that says "Bikes use shoulder only". Which now that I think about it, is pretty funny. Who in their right mind would ride anywhere but the shoulder on an interstate?

I totally agree, and there is a piece of single track from my house that connects with the urban trail system that would get me into town. The one thing that Google maps does not show is the massive amounts of snow on the ground right now. In the Spring and Summer that will be a fun option.

*eyes the Advocacy and Vehicular Cycling forums* No comment.

Ah. Did not think about snow. I forget that not all parts of AZ are boiling hot retirement communities. ;-)

I'm in SoCal and usually ride HWY 1 (Pacific Coast Highway) at least once a week and HWY 101 occasionally. There are sections where, as cephy noted, don't have reasonable alternatives so are legal. Never really had any issues riding either except having to patch a couple of tubes once on 101. Tough to find pin holes with all the big trucks blowing by.

If it were legal to ride on the interstate here I'd do it a lot. I think it would be the safest bike route I had to get to some destinations. On the interstate there's a full lane shoulder with rumble strips, nobody ever goes on it. The non-interstate route is narrow, lots of traffic, no shoulder, and the pavement is in bad shape.

I would go for I 17. Ear Plugs.

Its not that bad and can be quite relaxing with a wide shoulder. (your not looking over your shoulder for traffic)
I think they both would be safe. i 17 should be plowed first.