[Converting the OPs comment into an answer]

Found the answer: Draw an arrow path with a double line and at the same place draw a path with one line and voila - "triple" lined arrow.

```
triplearrow/.style={
draw=black!75,
color=black!75,
thick,
double distance=4pt,
<-,
>=stealth
},
thirdline/.style={
draw=black!75,
color=black!75,
thick,
<-,
>=stealth
}
```

You can use the `<coordinate>!<number>!<second coordinate>`

syntax; for example `(3,3)!.25!(0,0)`

means "the coordinate that is one quarter on the way from `(3,3)`

to `(0,0)`

". To place the label in the middle of the arrow, use the `midway`

option. An example:

```
\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}
\coordinate (a) at (3,3);
\coordinate (b) at (3,0);
\coordinate (c) at (-3,3);
\node (O) at (0,0) {origin};
\draw[->,red] (3,3) -- ( $ (a)!.25!(0,0) $ ) node [midway, sloped, above] {12 m/s};
\draw[->,blue] (b) -- ( $ (b)!.8!(0,0) $ ) node [midway, sloped, above] {12 m/s};
\draw[->,magenta] (c) -- ( $ (c)!.5!(0,0) $ ) node [midway, sloped, above] {12 m/s};
\end{tikzpicture}
\end{document}
```

Even closer to waht you need, is the `<coordinate>!<dimension>!<second coordinate>`

syntax, which means "use the point that is distanced
`<dimension>`

from `<coordinate>`

on the straight line from `<coordinate>`

to `<second coordinate>`

". A little example:
:

```
\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}
\coordinate (b) at (3,0);
\node (O) at (0,0) {origin};
\draw[->,magenta] (b) -- ( $ (b)!3cm!(0,0) $ ) node [midway, sloped, above] {12 m/s};
\end{tikzpicture}
\end{document}
```

And, of course, you can wrap this in a macro, as the following example suggests. The `\arrowfromto[<attributes>]{<initial coordinate>}{<to coordinate>}{<distance>}{<label>}`

macro will apply `\draw`

with the options given in the first optional argument, from `<initial coordinate>`

to a point that is `<distance>`

far away from it and on the straight line from `<initial coordinate>`

to the `<to coordinate>, using a label given by`

`:

```
\documentclass[12pt]{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}
% syntax
% \arrowfromto[<attributes>]{<initial coordinate>}{<to coordinate>}{<distance>}{<label>}
\newcommand\arrowfromto[5][blue]{%
\draw[#1] #2 -- ( $ #2!#4!#3 $ ) node [midway, sloped, above] {#5}}
\coordinate (a) at (3,3);
\node (O) at (0,0) {$O$};
\node (a) at (0,3) {$a$};
\node (b) at (3,3) {$b$};
\arrowfromto{(O)}{(a)}{5cm}{5cm};
\arrowfromto[-latex,red]{(a)}{(b)}{3cm}{3cm};
\arrowfromto[<->,green!80!black]{(b)}{(O)}{10mm}{10mm};
\end{tikzpicture}
\end{document}
```

## Best Answer

There are a number of ways you can do this in TikZ. Here are three examples:

which produces