Live/work has often been portrayed as an urban pioneering experience, pursued in industrial wastelands and commercial warehouse loft districts built to be abandoned at night by all but the night shift and the odd all-night diner. Actually a typical live/work resident today has three phone lines (including a dedicated internet connection), drinks exotic coffee drinks and wants a safe walk to it. That is the future of this use, although of course the older legends persist and do have some basis in reality.
When one really does live and work in the same place, one spends a tremendous amount of time in one's space, and in one place. As such, one begins to really care about that place, which includes the neighborhood around it. The SOHO phenomenon-- i.e. the colonization of neighborhoods pioneered by brave souls-- is still going on, but urban planners and regional scale developers are now envisioning live/work as integral to a full-blown version of urban revitalization-- and it includes urban amenities, such as Starbucks, bed and bath emporia, art galleries, and hopefully some actual neighborhood-serving services, such as dry-cleaners, grocery stores, shoe repair shops, pharmacies, etc. In short, live/work is part of a new wave of re-inhabitation of America's city centers by those who grew up in the suburbs, maybe went to college in the city, maybe raised kids in the suburbs but now want to be where the action is. And though they may drive Urban Assault Vehicles, they don't want to get into them every time they need a quart of milk or a latte.
While more study of the parking and traffic implications of live/work are needed, experience has shown that unless the individual spaces are quite large (say 2000+ s.f.) and/or are configured with separate work spaces, two spaces (maximum 2-1/2) per unit should be enough even when employees and walk-in trade are permitted. Local zoning standards for parking requirements should apply to separated work spaces or unit areas in excess of 2000 square feet, subtracting for the residents' use of that space.