Upgrades to the tangled web of interchanges from the I-26 intersection at Interstate 40 through the gnarled conduit of traffic on the Bowen Bridge have been on the N.C. Department of Transportation’s radar since at least 1989. Along the way, business groups, community members, environmental advocates, designers and elected officials have all weighed in with differing visions about how the project should function and look — and whether it should happen at all.