[SCR] jASH(v1).

/*
    Author: Johurt(ES.^, Edgar).
        Date: 15-01-2013.
    Video: http://www.youtube.com/watch?v=2MQDDcyU-jw
 */
#include <a_samp>

#define R_SPEED     50
#define A_SPEED     50
#define R_TIME      200
#define A_TIME      200

new rSpeed[MAX_PLAYERS], rSpeedTimer[MAX_PLAYERS],
    aSpeed[MAX_PLAYERS], aSpeedTimer[MAX_PLAYERS];

public OnPlayerConnect(playerid)
{
    rSpeedTimer[playerid] = -5;
    aSpeedTimer[playerid] = -5;
    return 1;
}

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
    if(newkeys & 262144)
    {
        if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER && !IsPlayerNPC(playerid) && rSpeedTimer[playerid] == -5)
        {
            rSpeed[playerid] = GetVehicleSpeed(GetPlayerVehicleID(playerid));
            rSpeedTimer[playerid] = SetTimerEx("CheckSpeed", R_TIME, false, "dd", playerid, 0);
        }
    }
    if(newkeys & 4)
    {
        if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER && !IsPlayerNPC(playerid) && aSpeedTimer[playerid] == -5)
        {
            aSpeed[playerid] = GetVehicleSpeed(GetPlayerVehicleID(playerid));
            if(aSpeed[playerid] > 50) aSpeedTimer[playerid] = SetTimerEx("CheckSpeed", A_TIME, false, "dd", playerid, 1);
        }
    }
    return 1;
}

forward CheckSpeed(playerid, mode);
public CheckSpeed(playerid, mode)
{
    if(IsPlayerNPC(playerid) || !IsPlayerConnected(playerid) || GetPlayerState(playerid) != PLAYER_STATE_DRIVER) return 1;
    new nSpeed = GetVehicleSpeed(GetPlayerVehicleID(playerid)), str[78];
    if(mode == 0)
    {
        rSpeedTimer[playerid] = -5;
        if(rSpeed[playerid] - R_SPEED > nSpeed)
        {
            format(str, 77, "Old speed: {d4650b}%d {ffffff}km/h, New speed: {d4650b}%d {ffffff}km/h.", rSpeed[playerid], nSpeed);
            SendClientMessage(playerid, -1, str);
            SendClientMessage(playerid, -1, "Don't use cheats!");
        }
    }
    else
    {
        aSpeedTimer[playerid] = -5;
        if(nSpeed > aSpeed[playerid] + A_SPEED)
        {
            format(str, 77, "Old speed: {d4650b}%d {ffffff}km/h, New speed: {d4650b}%d {ffffff}km/h.", aSpeed[playerid], nSpeed);
            SendClientMessage(playerid, -1, str);
            SendClientMessage(playerid, -1, "Don't use cheats!");
        }
    }
    return 1;
}

stock GetVehicleSpeed(vehicleid)
{
    new Float:spd[4];
    GetVehicleVelocity(vehicleid, spd[0], spd[1], spd[2]);
    spd[3] = floatsqroot(floatpower(floatabs(spd[0]), 2.0) + floatpower(floatabs(spd[1]), 2.0) + floatpower(floatabs(spd[2]), 2.0)) * 170.3;
    return floatround(spd[3]);
}