I bet the environmentalists are ecstatic about this. They are probably waiting in line to ride the trails......LOL!!

I'm an environmentalist and couldn't be more happy. Mountain biking has a much lower impact on trails than horses.
If the only reason to keep bikes off of park trails is erosion and negative impacts they should have kicked horses out a long time ago.
This is actually the first good thing Bush has done in nearly 8 years as president.

I think the real reason they don't allow bikes on trails is because in general bikers and hikers don't mix too well.

with the price of gas and the amount available , we'll all be biking

Well, it seems to make sense to me. Mountain biking probably has a bigger impact than hiking, but probably less than horseback riding. It's not noisy, and people have to move under their own power. I can see how bikers speeding down trails might be dangerous to hikers, but if the decisions are made judiciously by park managers familiar with the area and the impacts, I don't think it would really be a bad thing.

Better that than the ATV riders who afflict unregulated areas.

I wrote a ten page paper in college about this 4 years ago, and I'm so glad Washington finally came to its senses. The wilderness act written in 1934 lists pedal bikes as "mechanized vehicles" (which is the same category for cars and trucks); this categorization is the only reason why bike are currently banned from national parks. As far as trail erosion goes, on gradients less than 10% there is no difference of erosion caused by bikers and hikers. On steeper slopes bikes do cause more trail erosion, due to braking, but also on steeper slopes hikers are much more likely to create high erosion sort cut trails. Hikers also put more stress on wildlife than bikers because hikers are more likely to see animals and try and get closer to them while bikers in large part don't notice the animals (U of MT study 1994). While biking may not be a good idea for places like Zion and Yosemite it will be perfect for the lesser visited parks like Canyon Lands, and Great basin. This is such exciting news for me, Hurray!!!!!!!

Mountain biking is the best activity in the world. It's the horses that ruin the trails for the mountain bikers. Mountain biking causes no harm to the environment--those that argue it does have no idea what they are talking about. If you are concerned about erosion as a result of a one-foot wide mountain trail, then you have some serious issues and need to get some help.

I think this is a great idea. i love mountain biking and have always wished that there were mountain bike trails in the NP's. And I too agree that bikers cause very little erosion, especially compared to horses.