As a pet owner, your number one goal is to keep your pet safe, but nervous dogs can make that goal hard to meet, even if you don't realize it. Some pets are naturally nervous, but can still be helped by a few adjustments to their environment. If you can't find ways to calm your pet, he or she can be dangerous to themselves or others.
One solution is an underground pet fence. Pets who are nervous may become even more nervous with a fence they can see. It can make them feel caged in and stressed. An underground fence will keep your pet safe from oncoming traffic, but won't promote that sense of being trapped -- something that can make any animal edgy.
Another convenient option is a pet door. When your pet has the option to come in and go out as they please, they start to develop a sense of independence and confidence. Not only do you have a calmer pet, you have fewer “accidents,” because your pet can go out when they need to, and their reduced nervousness leads to better bladder control. It's also a convenience for you because you don't have to stop what you are doing to let your pet in or out.
Sometimes pets are nervous because of past experiences, but more often than not their nervousness can be reduced with a few adjustments to their environment. Nervous pets are also more prone to biting or attacking, so making a few adjustments means your pet is happier and safe for others to be around.