Keep safe distance

This is a flag raised by KaDeuber in her comments and I think this subject can be explored in one post here in LTTMMA.

Keeping safe distance is applicable in two major circumstances as far as I can see:

1. Amongst vehicles;
2. Among people.

Amongst vehicles

The Brazilian and the American versions of the driver's manual both contain the advice for keeping safe distance from the vehicles that surround you.

I keep safe distance from the vehicle ahead, but somehow, as KaDeuber mentioned, there is always a specific kind of driver who thinks that I am too slow to catch up with the traffic flow and insists to use that "empty" space, forcing me to step on the brakes. This kind of driver does NOT realize what "safe distance" means.

I personally follow the simple count-to-three-mississipi rule. I look to the vehicle that is in front of mine, spot a fixed reference in the road (a pole, one particular lane strip, some guard-rail, whatever) and count: one-mississippi-two-mississippi-three-mississippi. When I stop counting I must be at most right at the previously spotted fixed reference. If I have already passed by the reference when I finished counting, this means that the distance between my car and the vehicle in front of mine is not safe.

The timing rule is good because it takes into account the velocity you are developing. The velocity is calculated by dividing the variation of distance and the time spent. So, keeping the time constant (three-mississippi), the faster you are going, the farther you will be from the vehicle ahead, then you will have more space to maneuver your car if something happens.

E.g.: if you are driving at 20 mph (about 32 km/h), using the two-mississippi rule you will be about 59 ft (~18 m) of distance away from the other car; using the three-mississippi rule you will be 88 ft (~27 m) from the other car. Check the Table I below:

Velocity	two-mississippi	three-mississippi
20 mph (~32 km/h)	59 ft (~18 m)	88 ft (~27 m)
50 mph (~80 km/h)	147 ft (~45 m)	220 ft (~67 m)
80 mph (~128 km/h)	235 ft (~72 m)	350 ft (~107 m)

Table I: Distances between vehicles according to velocity, assuming that both vehicles are at the same speed.

So, for the drivers who think that there is an "empty" space between my car and the vehicle ahead, please be aware that there is no such thing as an "empty" space. That is a virtually occupied space for REAL safety reasons.

Among people

There are some annoying people that do not know that there is an invisible social delimited boundary between two individuals that are talking to each other. This kind of person can be called a close-talker according to The Seinfeld Dictionary. This site mentions an episode of Seinfeld where Jerry says: “Conversational distance, don’t you hate these people that talk to you, they talk into your mouth like you’re a clown at a drive-through”. Simply hilarious and truthfully, this Little Thing Makes Me Angry.

Here in the US, I have received some Webinar instruction regarding Business Etiquette that was included in the relocation package. The "close talker" problem must be so serious that the Webinar instructs you that you shall be at least 2-feet away from the other person in order to have a conversation.

So, for the "close talker" kind of people please, keep safe distance!