Are tribal police able to make traffic stops and make arrests on tribal land which is also a public hwy?

Yes, tribal police have the authority to make traffic stops and arrests on tribal land, including public highways that run through reservations. Their jurisdiction typically includes enforcing tribal laws and regulations, which can extend to state and Federal Laws depending on agreements or compacts with state authorities. However, the specifics can vary based on the tribe's sovereign status and any applicable legal agreements with neighboring jurisdictions.