Originally Posted by
steph746
Would an upright style bike be less safe? It seems that a rider would have more control in a hunched over position.
Depends on the rider. Been riding bicycles since the 1960s. For me, a more-upright flat bar or riser bar seating arrangement gives me more control of the front end. But, like as not, that's merely a result of not having had nearly as much saddle time in a drop-bar type position. I generally like a wider position for my hands. I generally like a somewhat or even nearly upright riding position, as it gives me a better view and turns out to provide more comfort. Has for decades. Can't say that that'd be the case for everyone. But I'd bet most people can, with sufficient saddle time, get comfortable and competent with a variety of positions, bikes.
Also, the tires are thinner. Would thinner tires mean that they are more vulnerable to flats?
Possibly. A wider rim that sports a tire with greater volume can suck up more punishment, all things being equal. (Much like, say, a 29er rim+tire as compared to a 20-incher ... but with same tire, same puncture protection, same essential construction, with volume/size being the main difference.)
In whatever size rim and tire you get, if you're concerned about punctures or pinch flats, consider going to a tougher (and heavier) tire. Something with a stronger/thicker puncture protection layer, like what the Schwalbe Marathon Plus, Continental Ride Tour, or similar. One can find tires that have tougher anti-puncture features, along with a more speed-friendly tread design, but they're almost universally heavier than their speedier cousins (those without that level of puncture protection).