Welcome to the forums.

40 kmph (25 mph) is not fast, at all, in fact its the lowest speed main roads can be in north america.

It really sounds like you need to map your routes better and work on situational awareness, as well as realize that bikes come in sizes like shoes and you should never be riding anything other than the correct size as it can cause joint issues and can be unsafe.

You really need to do a bit of homework before you even begin to look at bikes.

Bicycle - Wikipedia, the free encyclopedia

Hope you sort things out & find the thing that works best for you once you have some knowledge. I encourage you to poke around on this site as well for the numerous good threads and countless juicy tidbits on what works or doesn't & why/why not.

- Andy