If you are looking for a "robust"knife check out Cold Steel's SRK knife.The blade is 3/16" inch thick and six inches long.They are around seventy dollars but you can get them cheaper if you order a factory 2nd.I also agree with the others as to check local laws and carry in the trunk.I do not like it but there are more laws restricting knives than guns.The knife was one of mans first tools. It seems it is harder to carry one than a gun.Before I get shot let me say that I also believe in the right to bear arms.I believe this to include edged tools and weapons.