Could St. George really double its population over the next 20 years? According to state demographers, the answer is a definitive yes, and then some. The city proper is expected to grow from some 89,000 people today to more than 225,000 by 2040, a figure that should raise the eyebrows of anyone who’s found themselves frustrated by traffic, dust, long lines and other challenges brought on by the area’s fast-paced growth in recent years. But a bigger population could also mean bigger economic opportunities, more services and amenities, and more of a chance for arts and culture to thrive. As city managers try to wrap their heads around the best way to promote the “smart growth” that most of the area’s elected officials say they want to pursue, they’re reaching out for more public input.